Which statement below correctly identifies a rule for assigning oxidation numbers?
a
Group IA (1A) elements have an oxidation number of -1.
b
Oxygen in most compounds has an oxidation number of +2.
c
Group IIA (2A) elements have an oxidation number of -2.
d
Group VIIA (7A) elements have an oxidation number of -1.
e
Hydrogen in most compounds has an oxidation number of -1.
d
Group VIIA (7A) elements have an oxidation number of -1.