Foundations - Topic A - Matter - Exercises - Page 23: A.2(b)

i. Ca: +2, H: -1 ii. Ca: +2, C: -1 iii. Li: +1, N: +1 and -1

i. Ca is a G-IIA metal, hence it will always have oxidation state of +2. Oxidation state of H should be -1 to balance the positive charge. ii. Ca is a G-IIA metal, hence it will always have oxidation state of +2. C should have oxidation state of -1 to balance the charge. iii. Li is a G-IA metal, hence it will always have oxidation state of +1. Here N has two oxidation states, +1 and -1.