1. Steps to make an electron dot diagram: 1.Write the elements symbol 2.Find out the # of valence electrons 3.Place one dot around the symbol for each valence electron (like dealing cards)

2. Molecule Molecule= another name for a covalent compound Diatomic molecule= a covalent compound that contains 2 of the same atoms bonded together Examples:H 2 -Hydrogen Cl 2 - Chlorine O 2 - Oxygen N 2 - Nitrogen F 2 - Fluorine Br 2 - Bromine I 2 - Iodine

3. REMEMBER! BrINClHOF- all of these need to be in pairs!

4. Polyatomic ions Polyatomic ion= two or more covalently bonded elements that form an ion with its own charge Polyatomics you need to know!! (SO 4 ) -2 : sulfate ion (CO 3 ) -2 : carbonate ion (PO 4 ) -3 : phosphate ion (NO 3 )-1 : nitrate ion (ClO 3 ) -1 : chlorate ion (OH) - : hydroxide ion

5. Review Questions! 1.What happens to electrons in covalent bonding? 2.What type of element is most likely to form covalent bonds? 3.How does an atom develop a charge? 4.What is the smallest molecule of a covalently bonded compound?

6. Metallic bonding Metallic bonding= the force of attraction between a positively(+) charged metal ion and the electrons in a metal, share electrons Electrons move throughout a metal Metals conduct electric current Metals can be reshaped (ductile and malleable) Metals bend without breaking

7. Cu 2. Metallic Bonds Metals do not hold electrons very well When metal atoms are bonded together, the electrons move between valence shells They do not stay around any particular atom, they “float” from atom to atom “Sea of Mobile Electrons” Referred to as a “Sea of Mobile Electrons” Mobility gives metals their properties Malleability Conductivity Luster Cu e- Metals are shiny because they have free electrons which can move about freely throughout the metal. When light shines on these electrons, they vibrate and instead of energy springing from atom to atom, it is reflected as visible light. This is what appears as the shininess of metals.

9. Review Questions! 1.What is a metallic bond? 2.How is the metallic bond different from a covalent bond?