Chapter 4 - Periodic Table PDF

1 1  Chapter 4 Atoms and Elements 2 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Elements Elements are pure substances that contain only one type of material, such as copper, Cu lead, Pb aluminum,...

1 1  Chapter 4 Atoms and Elements 2 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Elements Elements are pure substances that contain only one type of material, such as copper, Cu lead, Pb aluminum, Al The element copper consists of copper atoms. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Chemistry and the Elements Copyright © 2010 Pearson Prentice Hall, Inc. Chapter 1/4  Periodic Table The periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number (number of protons), electron configurations, and recurring chemical properties. This ordering shows periodic trends, such as elements with similar behavior in the same column. Rows are called PERIODS. Columns are called GROUPS. There are 118 elements: 1-94 exist naturally 95-118 have been synthesized First Periodic Table – Mendeleev - 1869 Print out those Flash Cards!!!  4.1 Elements and Symbols 8 Elements are pure substances from which all other things are built cannot be broken down into simpler substances are listed on the inside front cover of this text Learning Goal Given the name of an element, write its correct symbol; from the symbol, write the correct name. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Some Elements and Their Names 9 Element names come from planets, mythological figures, minerals, colors, geographic locations, and famous people. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Chemical Symbols 10 Chemical symbols represent names of elements consist of one to two letters and start with capital One-Letter Symbols Two-Letter Symbols C carbon Co cobalt N nitrogen Ca calcium F fluorine Al aluminum O oxygen Mg magnesium Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Names and Symbols: Common Elements 11 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Element Etymology 42 Greek / 23 Latin / 3 Russian / 5 :Anglo-saxon, German & Swedish 11 English / 1 @ Japanese, Sanskrit, Gaelic, Arabic & Spanish 14 are named after scientists - mendelevium (Dmitri Mendeleev), curium (Marie & Pierre Curie), einsteinium (Albert Einstein), fermium (Enrico Fermi),lawrencium (Ernest Lawrence), roentgenium (Wilhelm Röntgen), nobelium (Alfred Nobel) rutherfordium (Ernest Rutherford), meitnerium (Lise Meitner), seaborgium (Glenn T. Seaborg), bohrium (Niels Bohr), copernicium (Nicolaus Copernicus), oganesson (Yuri Oganessian) 5 are named after other elements · molybdenum from the Greek for lead, molybdos · platinum from the Spanish platina meaning “little silver” · radon from radium · zirconium fromthe Arabic zarkûnmeaning “gold-like” ·nickel from the German for “devil’s copper”.  · 2 of the elements stink - bromine means “stench” & osmium means “smells”. · France appears twice in the form of francium & gallium (from Gaul) and its capital city, Paris (in lutetium). · 8 first isolated from rocks quarried in a the small village of Ytterby in Sweden. · 4 are named in tribute to the village (ytterbium, erbium, terbium, yttrium). · 4 are named after planets (Earth – in the form of tellurium, Mercury, Neptune and Uranus); · 2 are named after dwarf plants (Pluto and Ceres), · 1 after a star (helium from the Greek for the sun – Helios); · 1 after an asteroid (Pallas) 13 Discover Magazine 20 are named after places: Americium – America/ the Americas Berkelium, Californium – University of California at Berkeley Copper - probably for Cyprus Darmstadtium – Darmstadt, Germany Dubnium – Dubna, Russia Europium – Europe Francium , Gallium – France (Gallia, Latin for France.) Germanium – Germany Hassium – Hesse, Germany Hafnium – Hafnia, Latin for Copenhagen Holmium – Holmia, Latin for Stockholm Polonium – Poland Lutetium – Lutecia, an ancient name for Paris Nihonium - Japan Magnesium – Magnesia prefecture in Thessaly, Greece Rhenium – Rhenus, Latin for the Rhine, a German province Ruthenium – Ruthenia, Latin for Russia Scandium – Scandia, Latin for Scandinavia Strontium – Strontian, a town in Scotland Thulium – Thule, a mythical island Named after the minerals where they are found: calcium after Latin calx (lime), silicon is named after Latin silex (sand), sodium after soda and potassium after potash.  Practice 15 Write the correct chemical symbols for each of the following elements: A. iodine I B. iron Fe C. magnesium Mg D. zinc Zn E. nitrogen N Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Practice 16 Give the names of the elements with the following symbols: A. P = phosphorus B. Al = aluminum C. Mn = manganese D. H = hydrogen E. K = potassium Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Chemistry Link to the Environment: Carbon Atoms of carbon 17 can be arranged in different ways (forms) to give different substances called allotropes (from Ancient Greek allos meaning 'other’ & tropos meaning 'manner, form’) that exist in the same physical state. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  4.2 The Periodic Table The periodic table organizes 118 elements into groups with similar properties and places them in order of increasing atomic mass. Elements 1-98 occur naturally (can be found in nature, although a few last only millionths of a second). Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Periodic Table of Elements Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Groups and Periods On the periodic table, elements are arranged according to similar properties groups contain elements with similar properties in vertical columns periods are horizontal rows of elements, counted from top to bottom of the table as Periods 1−7 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Group Numbers Group numbers are written at the top of each vertical column and they use the letter A for representative elements (Groups 1A–8A) use the letter B for transition elements (Groups 3B–12B) An alternative system assigns numbers of 1–18 to all of the groups from left to right across the periodic table Because both systems are currently in use, they are both shown on the periodic table in this text and are included in our discussions of elements and group numbers. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Names of Groups Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Alkali Metals Group 1A, the alkali metals, includes lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Sodium - Na Stored under oil Reacts violently with air (water)  Halogens 26 Group 7A, the halogens, includes chlorine (Cl), bromine (Br), and iodine (I). Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Fluorine Bromine Chlorine Group 8 Nobel or Inert Gases Electrical current excites the elements and creates color  Neon lights & colors 29  Metals, Nonmetals, and Metalloids The heavy zigzag line separates metals and nonmetals. Metals are located to the left. Nonmetals are located to the right. Metalloids are located along the heavy zigzag line between the metals and nonmetals. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Metals, Nonmetals, and Metalloids and the Periodic Table Insert figure 4.6 page 102 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Characteristics of Metals, Nonmetals, and Metalloids Metals are shiny and ductile(easily molded/hammered or drawn into wires are good conductors of heat and electricity Nonmetals are dull, brittle, and poor conductors are good insulators Metalloids are better conductors than nonmetals but not as good as metals are used as semiconductors and insulators Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Comparing a Metal, Nonmetal, and Metalloid Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Solution Identify each of the following elements as a metal, nonmetal, or metalloid. A. sodium metal B. chlorine nonmetal C. silicon metalloid D. iron metal E. carbon nonmetal Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Chemistry Link to Health Of all the elements, 20 are essential for the well-being and survival of the human body four elements—oxygen, carbon, hydrogen, and nitrogen— make up 96% of our body mass Macrominerals—Ca, P, K, Cl, S, Na, and Mg—are representative elements involved in the formation of bones and teeth maintenance of heart and blood vessels, muscle contraction, nerve impulses, and acid–base balance of body fluids regulation of cellular metabolism Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Chemistry Link to Health Insert picture of periodic table with elements highlighted bottom of page 103 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  4.3 The Atom An atom is the smallest particle of an element that retains the characteristics of that element. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Dalton’s Atomic Theory In Dalton’s atomic theory, atoms are tiny particles of matter of an element are similar to each other and different from those of other elements of two or more different elements combine to form compounds are rearranged to form new combinations in a chemical reaction Atoms are never created or destroyed during a chemical reaction. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Electrical Charges in an Atom Atoms contain subatomic particles. Protons have a positive (+) charge. Electrons have a negative (–) charge. Neutrons are neutral. Like charges repel and unlike charges attract. Think of a magnet. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Structure of the Atom An atom consists of a nucleus that contains protons and neutrons electrons in a large, empty space around the nucleus Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Mass of the Atom – Atomic Mass Unit One atomic mass unit (amu) has a mass equal to one-twelfth of the mass of the carbon-12 atom. It is a unit of measurement for atoms and molecules A proton has a mass of about 1 (1.007) amu. A neutron has a mass of about 1 (1.008) amu. An electron has a very Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Subatomic Particles in the Atom In comparison Electrons are much smaller than to a proton protons or neutrons. If an electrons and neutron were the mass of a penny, a proton an electron’s or a neutrons would have the mass mass is of a large bowling ball! negligible. https://chem.libretexts.org/Courses/Palomar_College/PC%3A_CHEM100_- _Fundamentals_of_Chemistry/04%3A_Atoms_and_Elements/5.4%3A_The_Properties_of_Protons %2C_Neutrons%2C_and_Electrons Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Solution Which of the following subatomic particles fits each of the descriptions below? proton neutron electron A. found outside the nucleus B. has a positive charge C. has mass but no charge Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  4.4 Atomic Number and Mass Number All atoms of an element have the same number of protons and the same atomic number. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Atomic Number The atomic number is a whole number specific for each element is the same for all atoms of an element is equal to the number of protons in an atom appears above the symbol of an element in the periodic table Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Atomic Number = Protons in an Atom The atomic number represents the number of protons. For example, the atomic number of H is 1; every H atom has one proton the atomic number of C is 6; every C atom has six protons the atomic number of Cu is 29; every Cu atom has 29 protons Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Atomic Number = Protons in an Atom Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Atoms Are Neutral For neutral atoms, the net charge is zero. number of protons = number of electrons Aluminum has 13 protons and 13 electrons. The net (overall)charge is zero. 13 protons (13+) + 13 electrons (13–) = 0 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Practice Use the periodic table to fill in the atomic number, number of protons, and number of electrons for each of the following elements: Element Atomic Protons Electrons Number N Zn S Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Mass Number represents the number of particles in the nucleus is equal to the number of protons + the number of neutrons is always a whole number This is simply a count of the particles Also referred to as the atomic weightca present(depends on the isotope. does not appear in the periodic table (well, not officially) Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Composition of Some Atoms of Different Elements Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Study Tips: Protons and Neutrons Number of protons = atomic number Number of protons + number of neutrons = mass number Number of neutrons = mass number – atomic number Note: Mass numbers are given for specific isotopes only. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Practice An atom of lead (Pb) has a mass number of 207. A. How many protons are in the nucleus? B. How many neutrons are in the nucleus? mass number – number protons = number neutrons C. How many electrons are in the atom? Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. 4.5 Isotopes and Atomic Mass Mass number Atomic number Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Isotopes Isotopes are atoms of the same element have different mass numbers have the same number of protons but different numbers of neutrons can be distinguished by their atomic symbols Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Atomic Symbols and Subatomic Particles Examples of numbers of subatomic particles for atoms Atomic symbol 16 31 65 O P Zn 8 15 30 18 p+ 15 1 p + 30 1 p + 38 n 16 3 n 35 3 n 28 e− 15 2e − 30 2 e − Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Naturally occurring carbon consists of three isotopes: 12C, 13C, and 14C. State the number of protons, neutrons, and electrons in each of the following: Isotope 12 C 13 C 14 C protons 6 6 6 neutrons 6 7 8 electrons 6 6 6 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Practice Write the atomic symbols for atoms with the following subatomic particles: A. 8 protons 8 neutrons 8 electrons B. 17 protons 18 neutrons 17 electrons C. 47 protons 60 neutrons 47 electrons Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  https://www.youtube.com/watch ?v=faB9Gb7bl9I&index=1&list= PLLG7h7fPoH8Ixhq05cFNvgAt3 xIklAfJ3 60 Stop at 1:53… the rest will be covered in Chpt 5 (watch then!) Isotopes of Magnesium Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Isotopes and Element Mass Calculations Out in the world… you will find these elements existing with different isotopes. This means, that there are elements with different masses due to the different number of neutrons. To determine the actual mass of that element, we must take into consideration all of the different masses and how much (%) of each is there! What does each isotope CONTRIBUTE to the overall mass? Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Calculating Atomic Mass ~ Calculating your Class Grade Sometimes everything is worth Most times, things are not the same amount equal.  You would add up all  Exams are 70% the quizzes, exams and  Quizzes are 30% homework grades and divide by the total. Exam average x 0.70  Everything is worth Quiz average x 0.30 the same Adds up to your total “weighted “grade  Calculating Atomic Mass Atomic mass is the weighted average of all naturally occurring isotopes of an element number on the periodic table below the chemical symbol with two decimal places when we are looking at subatomic particles, we use amu’s to represent the mass units when we start looking at quantities on a much larger scale (like mixing compounds together) we use units of grams and call it the molar mass and molecular weight Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. I am selling apples – I have 100 of them. I don’t want to carry a scale around with me when I sell them, so I want to find out the AVERAGE mass. I decide to weigh them ALL before I leave the farm. Here is what I have: 30 apples weigh 62g and 70 apples weigh 95g Percentage-wise, 30% weight 62g and 70% weigh 95g. I could add up ALL the numbers individually, but there is a quicker way. Since 30% weigh 62g  0.30 x 62 = 18.6g 70% weigh 95g  0.70 x 95 = 66.5g 100% of the bucket has an average mass of  85.1g It is true some are more and some are less – but it’s the average. When you “average” two numbers together, you are saying they both hold equal importance (weight) – each one is “worth” 50%. Take 60 and 92. Find the “average” of both numbers. 60+92 152 --------- = ------- = 76 2 2 Now – you have two isotopes found in equal amounts (half the sample is one, the other half is the other, so each 50%) one weights 60amu the other 92amu. 50% of 60 = 50/100 * 60 = 30 50% of 92 = 50/100 * 92 = 46 ---------------------------------------- 100% of your sample = 76 amu average weight It’s still a “weighted” sample – just that there are equal amounts of each one of the isotopes. Calculating Atomic Mass To calculate atomic mass, use an experimental percent abundance of each isotope of the element multiply the percent abundance (how much is there of each isotope) by the atomic mass of that isotope (how much does it weigh) sum the total mass of each isotope Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Calculating Atomic Mass To calculate atomic mass of chlorine, use experimental data for both isotopes. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Study Check Gallium is an element found in lasers used in compact disc players. In a sample of gallium, there is 60.10% of 69Ga (atomic mass 68.926) atoms 39.90% of 71Ga (atomic mass 70.925) atoms What is the atomic mass of gallium? Remember – it’s just saying that 60.10% of the Ga found weighed 68.926g and 39.90% weighed 70.925g. It adds up to 100% of the Gallium sampled in nature. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Practice To calculate the atomic mass of gallium, first we multiply the atomic mass of each isotope by the percent abundance of that isotope divided by 100. Second, to calculate the atomic mass of gallium, we add the atomic mass calculated from each isotope. 31 Ga 69.72 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Atomic Mass Calculations Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Extra Practice ? Find the atomic mass of Mg (should be close to Periodic Table).  4.6 Electron Energy Levels A rainbow forms when light passes through water droplets. Learning Goal Given the name or symbol of one of the first 20 elements in the periodic table, write the electron arrangement. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Electromagnetic Radiation = Energy We experience electromagnetic radiation in different forms, such as light, the colors of a rainbow, or when we have an X-ray taken. Electromagnetic radiation consists of energy particles that move as waves of energy. The distance between the peaks of waves is called the wavelength. High-energy radiation has shorter wavelengths. Low-energy radiation has longer wavelengths. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Wavelength and Frequency Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Wavelength and Frequency Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Electromagnetic Spectrum ROYGBIV Red Orange Yellow Green Blue Indigo Violet The electromagnetic spectrum (energy spectrum) shows the arrangement of wavelengths of electromagnetic radiation. The visible range (what we can see) is from 700 to 400 nm.  Atomic Spectrum When light from a heated element passes through a prism, it separates into distinct lines of color separated by dark areas called an atomic spectrum. Each element has its own unique atomic spectrum. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Flame Test Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. 80  Electron Energy Levels The lines in an atomic spectrum are associated with the changes in energies of the electrons. In an atom, each electron is assigned a specific energy level. Energy levels are assigned principal quantum numbers: (n) = (n = 1, n = 2, …..) increase in energy as the value of n increases and they are farther away from the nucleus The energy of an electron is quantized—it can have only specific energy values. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Changes in Electron Energy Level Electrons move to a higher energy level when they absorb energy. When electrons fall back to a lower energy level, light is emitted. The energy emitted or absorbed is equal to the differences between the two energy levels. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Electrons and Energy Levels Electrons with the same energy are grouped in the same energy level. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. https://www.learner.org/wp-content/interactive/periodic/elementary2.html  https://youtu.be/uXUqWlcZrss 85 86  Electron Arrangements in Period 1 Period 1 Energy Level 1st 1 H 1 2 He 2 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Electron Arrangements in Period 2 Period 2 Energy Level 1st 2nd 3Li 2 1 4Be 2 2 5B 2 3 6C 2 4 7N 2 5 8O 2 6 9F 2 7 10Ne 2 8 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Electron Arrangements in Period 3 Period 3 Energy levels 1st 2nd 3rd 11Na 2 8 1 12Mg 2 8 2 13Al 2 8 3 14Si 2 8 4 15P 2 8 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Electron Arrangements in Period 4 Period 4 Energy Level 1st 2nd 3rd 4th 19K 2 8 8 1 20Ca 2 8 8 2 What do you notice in regard to when there is a new shell???? The shells fill up with 8 electrons. This is called an “octet”. How do you determine the number of electrons? ATOMIC NUMBER! Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Electron Arrangements Beyond 20 Energy Level 1st 2nd 3rd 4th 5th 6th 7th Number of Electrons 2 8 18 32 32 18 8 (4th and 5th have “f” shell electrons – an additional 14) Electron arrangements are written as follows: O = 2,6 P = 2,8,5 Ca = 2,8,8,2 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Practice Write the electron arrangements for the following elements: C atomic number = Si atomic number = O atomic number = N atomic number = Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. 93  4.7 Trends in Periodic Properties Electron arrangements are an important factor in the properties of elements, such as atomic size, ionization energy, and metallic character. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Group Number and Valence Electrons For representative elements in Groups 1A (1)–8A (18), chemical properties are due to the number of valence electrons. Valence electrons are the number of electrons in the outermost energy level. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Group Number and Valence Electrons For representative elements in Groups 1A (1)–8A (18), chemical properties are due to the number of valence electrons. Valence electrons are the number of electrons in the outermost energy level. The group number gives the number of valence electrons for the representative elements. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Group Number and Valence Electrons Group # #of Valence Electrons 1A (1) 1 2A (2) 2 3A (13) 3 4A (14) 4 5A (15) 5 6A (16) 6 7A (17) 7 8A (18) 8 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Group Number and Valence Electrons Group # #Valence Electrons 1A (1) 1 2A (2) 2 3A (13) 3 4A (14) 4 5A (15) 5 6A (16) 6 7A (17) 7 8A (18) 8 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Electron-Dot Symbols Electron-dot symbols are also known as Lewis structures represent the valence electrons as dots placed on the sides of a symbol For example, Al = 2,8,3 Three valence electrons are represented as dots. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Electron-Dot Symbol for Mg Possible electron-dot symbols for magnesium, with the electron arrangement of 2,8,2, include two valence electrons, represented as dots can be drawn in more than one way Electron-dot symbols for magnesium Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Practice Write the electron-dot symbol for each of the following elements: Chlorine Carbon Nitrogen Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Valence shell electrons & Octet Rule https://sciencenotes.org/what-are-valence-electrons-definition- and-periodic-table/ https://slidetodoc.com/octet-rule-chemical-bonding-the-octet-rule-is/ Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Atomic Size Atomic size is determined by the atom’s atomic radius, the distance between the nucleus and outermost electrons increases for representative elements from top to bottom of the periodic table (more electrons means more shells) decreases within a period as a result of the increased number of protons in the nucleus (more electrons in the same shell) Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. Atomic Size For representative elements, the atomic size increases going down a group but decreases going from left to right across a period. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Ionization Energy Ionization energy is the required energy to remove one of the outermost electrons (the valence electrons) Na(g) + energy (ionization)  Na+(g) + e− As the distance from the nucleus to the valence electrons increases, the ionization energy decreases. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Ionization Energy Ionization energy decreases down a group and increases across a period from left to right. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Metallic Character An element with metallic character is one that loses electrons easily. Metallic character is more prevalent in metals on the left side of the periodic table is less for nonmetals on the right side of the periodic table, which do not lose electrons easily Arsenic Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Metallic Character Metallic character of the representative elements increases going down a group & decreases going from left to right across a period. Calcium Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Summary of Trends in the Periodic Table Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc.  Practice CarbonNitrogen Chlorine Aluminum Which is the smallest atom? Which has the highest ionization energy? N Cl Which has the greatest metallic character?Al Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition © 2015 Pearson Education, Inc. (Electron affinity is how much an element would LIKE to have another electron in its outer shell. https://www.youtube.com/watch?v=fPnwBITSmgU Watch this!!! https://www.youtube.com/watch ?v=j7JcyDBHCBc&index=2&list =PLLG7h7fPoH8Ixhq05cFNvgAt 3xIklAfJ3  Professor Dave explains the Periodic Table https://www.youtube.com/watch?v=hePb00CqvP0 Stop at 4 minutes Start again at ~5:30 minutes General Overview of Periodic Table https://www.youtube.com/watch?v=wXRHz5ZEIK0