Electron and Orbital Configurations Ca Cl Na Cu

Periodicy The periodic table was proposed by Mendeleev in the 1860’s It correctly predicted the properties of new elements, making it a useful and powerful tool The vertical columns in the periodic table are called groups The horizontal rows in the periodic table are called periods

Important groups Group 1A – Alkali Metals Group 2A – Alkaline Earth Metals Group 7A – Halogens Group 8A – Noble Gases / Inert Gases

Elements can be divided into 3 categories Classes of Elements Elements can be divided into 3 categories Metals Non-metals Metalloids

Properties of Metals Good conductors of heat and electricity Solid at room temp. (exception: Hg) Most are malleable and ductile (can be made into wire) Groups 3-12 are called transition metals Have varied levels of reactivity

Properties of Non-Metals Poor conductors of heat and electricity All gases are non-metals Non-metals that are solid tend to be VERY brittle Varied levels of reactivity, however F is the most reactive non-metal, while Noble Gases tend to not react

Properties of Metalloids A metalloids ability to conduct electric current varies with temperature Metalloids’ properties tend to fall in between those of metals and non-metals Metalloids are B, Si, Ge, As, Sb, Te, Po, and At.

Alkali Metals Have 1 valence electron Most are exceptionally reactive Most alkali metals can not be stored with air, because they tend to react with water vapor Include Li, Na, K, Rb, Cs, and Fr

Alkaline Earth Metals Have 2 valence electrons All react with water except Be Mg and Ca are important in biological processes Mg is often used to make metals lighter without sacrificing strength