Oxidation States

Question 1

Remember, you are determining the oxidation state of a single atom

Question 2

The sum of oxidation state of a compound is ……..

Answer 2

NaCl

oxidation state of - Na+
oxidation state of - Cl-

sum of oxidation state = 0

Question 3

In molecules or compounds, the sum of the oxidation states on the atoms is

Answer 3

0

elements H in H2= 0

C in CO2= 4

O in CO2 =-2

Question 4

How do you determine which is the positive one in oxidation states of a compound e.g CO2

Answer 4

The more electronegative species will have the negative value

Electronegativity increases across a period and decreases down a group

O is further to the right than C in the periodic table so it has the negative value

Question 5

Rules for finding metals oxidation state

Answer 5

positive values in compounds

Value is usually that of the group number

Where there are several possibilities for oxidation state don’t go over group number

sn can be = 2+ or 4+

mn cane be = +2 +4 +6 +7

Question 6

Rules for finding non -metals oxidation state

Answer 6

negative values in compounds

cl usually -1

can have values up to group number - +1, +3,+5,+7