1. Ionic Bonds & Ionic Compounds Types of ions – Monatomic ions - ions formed from a single atom. Ca 2+, K +, Al 3+, Cu +, Cu 2+, Fe 2+, Fe 3+, Cl -, O 2-, N 3- – Polyatomic ions - ions formed from multiple atoms NH 4 +, CO3 2-, SO 4 2-, OH -, PO 4 3-

2. Monatomic ions Monatomic ions - ions formed from a single atom. – Metals form cations and retain their name – Some transition metals can form more that one cation (Cu +, Cu 2+, Fe 2+, Fe 3+ ) are named after their charge copper, copper II, iron II & iron III – Non - metals form anions (negative charge) are renamed with the suffix -ide (Cl - chlorine, Cl - - chloride)

3. Polyatomic ions Polyatomic ions - ions formed from multiple atoms – The atoms of a polyatomic ion are contain covalent bonds (shared electrons) but form an ion that participates in ionic bonding – Each polyatomic ion remains intact when forming ionic compounds

4. Binary Ionic Compounds Binary ionic compounds are formed from the union of 2 ions (cation & anion). The bond is relatively strong and the ratios of cations to anions is related to the charge on each ion. – The ionic compound is named after its components - NaCl is sodium chloride – The empirical formula (chemical formula) tells us about the exact numbers and ratios in the ionic compounds. The empirical formula only lists elements in their reduced quantities. Li + + O 2- a 2Li + O 2-  Li 2 O Lithium oxide Ca 2+ + 2Cl -  CaCl 2 Calcium chloride

5. Criss-Cross Method The criss-cross method is used to balance ionic charges when forming ionic compounds. – Simply put the charge (superscript number) as the opposite atom's subscript number. Then reduce. Mg 2+ + S 2-  Mg 2+ S 2-  Mg 2 S 2  MgS Magnesium sulfide (the ratio of the subscripts is reduced) K + + N 3-  K + N 3-  K 3 N Potassium nitride (the #1 is not written as a subscript) AL 3+ + O 2-  AL 3+ O 2-  AL 2 O 3 Aluminum oxide