Writing Ionic Compounds The “Swap & Drop” Method

Why do atoms form ions? All atoms want to gain stability. We need to look at the valence electrons of each atom. Valence Electrons: Electrons in the outermost energy level. All atoms want to get to eight valence electrons to become stable. “8 is Great!!!”

K Cl - + 1 1 Swap & Drop Method For Ionic Compounds Only! Potassium Ion K Chlorine Ion Cl - + 1 1 Step 1: Drop the signs.

K Cl 1 1 Swap & Drop Method Step 2: Swap Values. Potassium Ion Chlorine Ion Cl 1 1 Step 2: Swap Values.

K Cl 1 1 1 1 Swap & Drop Method Step 3: Drop Values to Subscripts. Potassium Ion K Chlorine Ion Cl 1 1 1 1 Step 3: Drop Values to Subscripts.

Swap & Drop Method Potassium Ion K Chlorine Ion Cl Potassium Chloride Step 4: When the values are the same, then they can be erased. The number (1) is never required.

Al O - + 3 2 Swap & Drop Method Step 1: Drop the signs. Aluminum Ion Oxygen Ion O - + 3 2 Step 1: Drop the signs.

Al O 3 2 Swap & Drop Method Step 2: Swap Values. Aluminum Ion Oxygen Ion O 3 2 Step 2: Swap Values.

Al O 2 3 2 3 Swap & Drop Method Step 3: Drop values to subscripts. Aluminum Ion Al Oxygen Ion O 2 3 2 3 Step 3: Drop values to subscripts.

Al O 2 3 Swap & Drop Method Step 4: Combine into compound. Aluminum Ion Al Oxygen Ion O 2 3 Aluminum Oxide Step 4: Combine into compound.