Redox.

Question 1

Oxidation number definition.

Answer 1

The number of electrons involved in bonding to a different element.

Question 2

Rules for oxidation numbers for elements.

Answer 2

Always zero.
Any bonding is to atoms of the same element.

Question 3

Rules for oxidation numbers of compounds and ions.

Answer 3

Each atom in a compound has an oxidation number.
Sign(-/+) comes before number.
Numerically the same as the ionic charge.
Special cases:
H in metal hydrides=-1.
O in peroxides=-1.
O bonded to F=+2.

Question 4

How to calculate oxidation numbers.

Answer 4

For combined atoms:
-Sum of oxidation numbers=total charge.
PRACTICE QUESTIONS.

Question 5

Writing formulae w/ oxidation numbers.

Answer 5

PRACTICE QUESTIONS.

Question 6

Rules for using roman numerals w/ oxidation numbers(naming).

Answer 6

Show the oxidation number of an element w/o a sign.
iron(II)=Fe2+ w/ ox number 2+.
Iron(III)=Fe3+ w/ ox number 3+.
NO2(nitrite)=Nitrate(III).
NO3(nitrate)=Nitrate(V).

Question 7

Oxidation definition.

Answer 7

Addition of Oxygen.
Loss of electrons.
Increase in oxidation number.

Question 8

Reduction definition.

Answer 8

Loss of Oxygen.
Gain of electrons.
Decrease in oxidation number.

Question 9

Redox reactions definition.

Answer 9

Involve reduction and oxidation.
If something is reduced, something else must be oxidised.
The electrons gained and lost balance.

Question 10

Equations and giving oxidation numbers.

Answer 10

PRACTICE QUESTIONS.

Question 11

Redox reactions w/ metals and acids.

Answer 11

Metal+acid–>salt+hydrogen.
Metal and H ions only change in terms of reduction/oxidation.
PRACTICE QUESTIONS.