Periodic Table PDF

Periodic Table Learning objectives:  Explain why chemists use the periodic table.  Identify the position of groups, periods and the transition metals in the periodic table  Periodic trends in ionization energy, atomic radius and electronegativity, and relate them to the atom...

Periodic Table Learning objectives:  Explain why chemists use the periodic table.  Identify the position of groups, periods and the transition metals in the periodic table  Periodic trends in ionization energy, atomic radius and electronegativity, and relate them to the atomic structures of the 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. Periodic Table  The periodic table organizes the elements according to their atomic number  A great deal of information about an element can be gathered from its position in the periodic table.  For example:  you can predict the physical and chemical properties of the element. The Periodic Law The repeating physical and chemical properties of elements change periodically with their atomic number. What’s in a square? Atomic number Symbol Average atomic mass Name Physical state 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. Atomic Mass Unit (AMU)  The unit of measurement for an atom is an AMU. It stands for atomic mass unit.  OneAMU is equal to the mass of one proton. Atomic Mass Unit (AMU)  There are 6 X 1023 or 600,000,000,000,00 0,000,000,000 amus in one gram.  (Remember that electrons are 2000 times smaller than one amu). Symbols  All elements have their C Carbon own unique symbol.  Itcan consist of a single capital letter, or a capital letter and one or Cu two lower case letters. Copper Common Elements and Symbols Classification of Elements in Periodic Table 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. Elements are arranged: Vertically into Groups (18) Horizontally Into Periods (7)  Families Periods  Columns of elements are called  Each horizontal row of groups or families. elements is called a period.  Elements in each family have  The elements in a period are similar but not identical not alike in properties. properties.  In fact, the properties change  For example, lithium (Li), sodium (Na), potassium (K), and other greatly across even given members of family IA are all soft, row. white, shiny metals.  The first element in a period  All elements in a family have the is always an extremely active same number of valence solid. The last element in a electrons. period, is always an inactive gas. In group Each atom has the same number of electrons in it’s outer energy level. Be (Beryllium) Atom Mg (Magnesium) Atom In period Each atom has the same number of electron holding shells. 4th Shell K Kr (Krypton) (Potassium) Atom Atom Fe (Iron) 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  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 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.  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.  Matter  Allmatter is composed of atoms and groups of atoms bonded together, called molecules.  Substances that are made from one type of atom only are called pure substances.  Substances that are made from more than one type of atom bonded together are called compounds.  Compounds that are combined physically, but not chemically, are called mixtures.  Elements, Compounds, Mixtures  Sodium is an element.  Chlorine is an element.  When sodium and chlorine bond they make the compound sodium chloride, Compounds have different commonly known as properties than the elements that table salt. make them up. Table salt has different properties than sodium, an explosive metal, and Elements, Compounds, Mixtures  Hydrogen is an element.  Oxygen is an element.  When hydrogen and oxygen bond they make the compound water.  When salt and water are combined, a mixture is created. Compounds in mixtures retain their The ocean individual properties. is a  Elements, compounds, and mixtures  Mixtures can be separated by physical means.  Compounds can only be separated by chemical means.  Elementsare pure substances. When the subatomic particles of an element are separated from its atom, it no longer retains the properties of that element. Trends in the Periodic Table  A trend is a predictable change in a particular direction.  Trends occur due to the electronic configurations of elements.  Across a period nuclear attraction increased due to increase in atomic number.  Down a group, nuclear attraction decreases due to “shielding effect”. Atomic Radius  Is a distance from center to electrons in outer energy level. Atomic Radius Trend Ionization energy trend  The energy required to remove an electron from an atom or ion Electronegativity trend  Ability of an atom in a chemical compound to attract electrons of chemical bond.  Electronegativity values generally decrease as you move down a group.  Electronegativity increases as you move left to right across a period. Electronegativity trend Increasing electronegativity de el c r ec ea tr si on n eg g at iv ity What is a COMPOUND?  A substance in which two or more different elements are CHEMICALLY bonded together. What is the chemical bond? Reference  General chemistry, Whitten.  Introduction to organic chemistry and biochemistry.  Internet.