Introduction: Periodic Table of Elements Science Links 2013-2014 The periodic table arranges information in a logical way. The columns of elements are called groups or families. Elements in the same family have similar properties Introduction: Valence Electrons: Each row is called a period. Elements within periods do NOT show similarities. In chemistry, valence electrons are the electrons contained in the outermost, or valence, electron shell of an atom. Helium atom model This helium (He) model displays two valence electrons located in its outermost energy level. Helium is a member of the noble gases and contains two protons, neutrons, and electrons. 1
Metals: Metals are found on the LEFT side of the periodic table. Metals Physical Properties: The physical properties of metals make them easy to identify. Metals: Conduct Heat Conduct Electricity Have a Bright Metallic Luster Are Malleable Have High Melting Points Give everyday examples of the above in your notes! Metals Chemical Properties: Non-Metals: Metal atoms can have 1, 2, 3, or 4 electrons in their outer shell. (Valence) This means they commonly share their electrons in chemical bonding. Non- Metals are found on right side of the periodic table. 2
Non-Metal Physical Properties: Non-Metal Chemical Properties: Non-Metals have no luster and are dull in appearance. They do NOT conduct heat or electricity very well. Non-Metals are often brittle and have lower densities and lower melting points than metals. Atoms of non-metals have 5, 6, 7, or 8 electrons in their outer energy level. This means that they tend to accept electrons when they combine chemically. Those with 8 valence electrons are stable and non-reactive. Metalloids: Zig Zag Stairstep divides metals and non-metals metaloids are on the border These elements have properties of both metals and non-metals. Metalloid means sort of metal Metalloids 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. 3
The Families Family 1: Family 2: The elements in family 1 (except hydrogen) are alkali metals. These atoms have 1 valence electron. They are the most reactive metals Alkali Metals: Li, Na, K, Rb, Cs, and Fr Elements in family 2 are the Alkaline Metals (or alkali Earth metals). They have 2 valance electrons. Alkaline Metals: Be, Mg, Ca, Sr, Ba, and Ra Families 3-12: Family 13: The elements in columns 3 to 12 are the transition metals. Transition metals are good conductors of heat and electricity, and are often highly colored. Examples: Zn, Hg, and Pt Family 13 is the Boron family. These elements have 3 valence electrons; Boron is the only non-metal, the other are metals. Aluminum is the most abundant metal on Earth. 4
Family 14: Family 15: Family 14 is the Carbon family. These atoms have 4 valence electrons. The metalloids include Silicon and Germanium, and the metals are Tin and Lead. Family 15 is the Nitrogen Family. These atoms have 5 valence electrons and tend to share electrons when they bond. Nitrogen is the most abundant element in the Earth s atmosphere. Family 16: Family 17: Family 16 is the Oxygen family, and these atoms have 6 valance electrons. These atoms also tend to share electrons when forming compounds. Oxygen is the most abundant element in the earth s crust and the 2 nd most in the atmosphere. Examples: S, Te, and Po Family 17 is known as the Halogen family. They have 7 valence electrons and are the most reactive non-metals. They only need to gain 1 electron and are not found as free atoms in nature. They often combine with the transition metals. Examples: Cl, I, and Br 5
Family 18: Periods The last family is known as the Noble Gasses. These elements are typically stable because their outer shell is full with 8 valance electrons. Most atoms strive to be like the Noble Gases. Examples: Ne, Ar, and Kr In the periodic table, elements have something in common if they are in the same row. All of the elements in a period have the same number of atomic orbitals. Every element in the top row (the first period) has one orbital for its electrons. Periods All of the elements in the second row (the second period) have two orbitals for their electrons. It goes down the periodic table like that. At this time, the maximum number of electron orbitals or electron shells for any element is seven. 6