Electronegativity / ion colors / Balancing Complex Half-Reactions

If the difference in electronegativity is <0.5, it is _____

nonpolar covalent

If the difference in electronegativity is >= 0.5, it is _____

polar covalent

What color are copper ions?

blue

What color are nickel ions?

green

What color are iron ions?

yellow/orange

What color are chromium (Cr) ions?

yellow/orange

What color are cobalt ions?

pink

How to Balance Complex Half-Reactions

1. Balance everything other than H and O

2. Balance O atoms by adding H2O molecules to the other side.

3. Balance H atoms by adding H+ ions to the opposite side.

4. Balance charge by adding electrons to the appropriate side (if necessary).