Periodic Table of Elements PDF

Periodic Table of Elements  Mendeleev ◼ In 1869, Dmitri Ivanovitch Mendeléev created the first accepted version of the periodic table. ◼ He grouped elements according to their atomic mass, and as he did, he found that the families had similar chemical properties. ◼ Bla...

Periodic Table of Elements  Mendeleev ◼ In 1869, Dmitri Ivanovitch Mendeléev created the first accepted version of the periodic table. ◼ He grouped elements according to their atomic mass, and as he did, he found that the families had similar chemical properties. ◼ Blank spaces were left open to add the new elements he predicted would occur.  chlorine nitrogen gold silver mercury oxygen hydrogen helium niobium sodium neodymium carbon Elements ◼ Science has come along way since Aristotle’s theory of Air, Water, Fire, and Earth. ◼ Scientists have identified 90 naturally occurring elements, and created about 28 others. Elements ◼ The elements, alone or in combinations, make up our bodies, our world, our sun, and in fact, the entire universe. Abundant Elements Periodic Table ◼ The periodic table organizes the elements in a particular way. A great deal of information about an element can be gathered from its position in the period table. ◼ For example, you can predict with reasonably good accuracy the physical and chemical properties of the element. You can also predict what other elements a particular element will react with chemically. ◼ Understanding the organization and plan of the periodic table will help you obtain basic information about each of the 118 known elements. Key to the Periodic Table ◼ Elements are organized on the table according to their atomic number, usually found near the top of the square.  The atomic number refers to how many protons an atom of that element has.  For instance, hydrogen has 1 proton, so it’s atomic number is 1.  The atomic number is unique to that element. No two elements have the same atomic number. What’s in a square? ◼ Different periodic tables can include various bits of information, but usually:  atomic number  symbol  atomic mass  number of valence electrons  state of matter at room temperature.  Atomic Number ◼ This refers to how many protons an atom of that element has. ◼ No two elements, have the same number of protons. Bohr Model of Hydrogen Atom Wave Model Atomic Mass ◼ Atomic Mass refers to the “weight” of the atom. ◼ It is derived at by adding the number of protons with the number of This is a helium atom. Its atomic Hmass is 4 (protons plus neutrons). neutrons. What is its atomic number? Atomic Mass and Isotopes ◼ While most atoms have the same number of protons and neutrons, some don’t. ◼ Some atoms have more or less neutrons than protons. These are called isotopes. ◼ An atomic mass number with a decimal is the total of the number of protons plus the average number of neutrons. Atomic Mass Unit (AMU) ◼ The unit of measurement for an atom is an AMU. It stands for atomic mass unit. ◼ One AMU is equal to the mass of one proton. Symbols ◼ All elements have C Carbon ◼ their own unique symbol. It can consist of a single capital letter, Cu or a capital letter and one or two lower case letters. Copper Common Elements and Symbols  Valence Electrons ◼ The number of valence electrons an atom has may also appear in a square. ◼ Valence electrons are the electrons in the outer energy level of an atom. ◼ These are the electrons that are transferred or shared when atoms bond together.  Properties of Metals ◼ Metals are good conductors of heat and electricity. ◼ Metals are shiny. ◼ Metals are ductile (can be stretched into thin wires). ◼ Metals are malleable (can be pounded into thin sheets). ◼ A chemical property of metal is its reaction with water which results in corrosion. Properties of Non-Metals ◼ Non-metals are poor conductors of heat and electricity. ◼ Non-metals are not ductile or malleable. ◼ Solid non-metals are brittle and break easily. ◼ They are dull. ◼ Many non-metals are gases. Sulfur Properties of Metalloids ◼ Metalloids (metal-like) have properties of both metals and non-metals. ◼ They are solids that can be shiny or dull. ◼ They conduct heat and electricity better than non- metals but not as well as metals. ◼ They are ductile and malleable. Silicon  Families Periods ◼ Columns of elements are ◼ Each horizontal row of called groups or families. elements is called a ◼ Elements in each family period. have similar but not ◼ The elements in a period identical properties. are not alike in properties. ◼ For example, lithium (Li), ◼ In fact, the properties change greatly across sodium (Na), potassium even given row. (K), and other members of ◼ The first element in a family IA are all soft, period is always an white, shiny metals. extremely active solid. The ◼ All elements in a family last element in a period, is have the same number of always an inactive gas. valence electrons. Hydrogen ◼ The hydrogen square sits atop Family AI, but it is not a member of that family. Hydrogen is in a class of its own. ◼ It’s a gas at room temperature. ◼ It has one proton and one electron in its one and only energy level. ◼ Hydrogen only needs 2 electrons to fill up its valence shell.  Alkali Metals ◼ The alkali family is found in the first column of the periodic table. ◼ Atoms of the alkali metals have a single electron in their outermost level, in other words, 1 valence electron. ◼ They are shiny, have the consistency of clay, and are easily cut with a knife. Alkali Metals ◼ They are the most reactive metals. ◼ They react violently with water. ◼ Alkali metals are never found as free elements in nature. They are always bonded with another element. What does it mean to be reactive? ◼ We will be describing elements according to their reactivity. ◼ Elements that are reactive bond easily with other elements to make compounds. ◼ Some elements are only found in nature bonded with other elements. ◼ What makes an element reactive?  An incomplete valence electron level.  All atoms (except hydrogen) want to have 8 electrons in their very outermost energy level (This is called the rule of octet.)  Atoms bond until this level is complete. Atoms with few valence electrons lose them during bonding. Atoms with 6, 7, or 8 valence electrons gain electrons during bonding. 5 Alkaline Earth Metals ◼ They are never found uncombined in nature. ◼ They have two valence electrons. ◼ Alkaline earth metals include magnesium and calcium, among others. Transition Metals ◼ Transition Elements include those elements in the B families. ◼ These are the metals you are probably most familiar: copper, tin, zinc, iron, nickel, gold, and silver. ◼ They are good conductors of heat and electricity. Transition Metals ◼ The compounds of transition metals are usually brightly colored and are often used to color paints. ◼ Transition elements have 1 or 2 valence electrons, which they lose when they form bonds with other atoms. Some transition elements can lose electrons in their next-to-outermost level. Transition Elements ◼ Transition elements have properties similar to one another and to other metals, but their properties do not fit in with those of any other family. ◼ Many transition metals combine chemically with oxygen to form compounds called oxides.  Boron Family ◼ The Boron Family is named after the first element in the family. ◼ Atoms in this family have 3 valence electrons. ◼ This family includes a metalloid (boron), and the rest are metals. ◼ This family includes the most abundant metal in the earth’s crust (aluminum).  Carbon Family ◼ Atoms of this family have 4 valence electrons. ◼ This family includes a non-metal (carbon), metalloids, and metals. ◼ The element carbon is called the “basis of life.” There is an entire branch of chemistry devoted to carbon compounds called organic chemistry.  Nitrogen Family ◼ The nitrogen family is named after the element that makes up 78% of our atmosphere. ◼ This family includes non- metals, metalloids, and metals. ◼ Atoms in the nitrogen family have 5 valence electrons. They tend to share electrons when they bond. ◼ Other elements in this family are phosphorus, arsenic, antimony, and bismuth.  Oxygen Family ◼ Atoms of this family have 6 valence electrons. ◼ Most elements in this family share electrons when forming compounds. ◼ Oxygen is the most abundant element in the earth’s crust. It is extremely active and combines with almost all elements.  Halogen Family ◼ The elements in this family are fluorine, chlorine, bromine, iodine, and astatine. ◼ Halogens have 7 valence electrons, which explains why ◼Halogen atoms only need they are the most to gain 1 electron to fill their active non-metals. outermost energy level. They are never found ◼They react with alkali free in nature. metals to form salts.  Noble Gases ◼ Noble Gases are colorless gases that are extremely un-reactive. ◼ One important property of the noble gases is their inactivity. They are inactive because their outermost energy level is full. ◼ Because they do not readily combine with other elements to form compounds, the noble gases are called inert. ◼ The family of noble gases includes helium, neon, argon, krypton, xenon, and radon. ◼ All the noble gases are found in small amounts in the earth's atmosphere. Rare Earth Elements ◼ The thirty rare earth elements are composed of the lanthanide and actinide series. ◼ One element of the lanthanide series and most of the elements in the actinide series are called trans-uranium, which means synthetic or man-made.  Assignment: ◼ Find out the trends of the following properties of elements: ◼ Atomic number ◼ Atomic mass ◼ Electronegativity ◼ Metallic property ◼ Non-metallic property  What are their trends from left to right – period  What are their trends from top to bottom – group  How are we going to explain these patterns?