Question

what is the oxidation state for each atom?
please help me :(
(Pt2O7)2-

Answer 1

Just remember Oxygen always have an oxidation state of -2 (Except for H2O2)
The total charge should be equal to -2 in (Pt2O7)2-
So,

2Pt+7(-2)=-2
Pt=+6

Answer 2

how about the oxidation state for oxygen?
O2 = -4 ?

Answer 3

If its diatomic or on its own such as Fe(s),Mg(s), then the charge is zero

Answer 4

ok. how about the oxidation state of oxygen in (Pt2O7)2-?
is it still O = -2?
or is it O = -14?

Answer 5

O is still -2,
but O7 is = -14

Answer 6

There are 7 oxygen atoms there, so if each oxygen atom is -2, then 7(-2)=-14

Answer 7

ooo. tq so much sam. :D really appreciate it