Oxidation, Reduction and Redox

Question 1

What is oxidation?

Answer 1

the loss of electrons

Question 2

What is reduction?

Answer 2

the gain of electrons

Question 3

What is an oxidising agent?

Answer 3

species that gains electrons

Question 4

What is a reducing agent?

Answer 4

species that lose electrons

Question 5

Define oxidation state

Answer 5

A number which represents the number of electrons lost or gained by an atom of that element in the compound

Question 6

What is the oxidation state of an element?

Answer 6

zero

Question 7

What do the oxidation states in neutral compounds add up to?

Answer 7

zero

Question 8

What do the oxidation states in a charged compound add up to?

Answer 8

the total charge

Question 9

What is the oxidation number of F?

Answer 9

always -1

Question 10

What is the most common oxidation number of O?

Answer 10

-2

Question 11

What exceptions are there to the oxidation of O where it is not -2?

Answer 11

• in peroxides, where O is -1
• when reacted with F, O is +2

Question 12

What is the most common oxidation number of Cl, Br and I?

Answer 12

-1

Question 13

When is the oxidation number of Cl, Br and I not -1?

Answer 13

it can be positive when bonded to F or O

Question 14

What is the most common oxidation number of H?

Answer 14

+1

Question 15

When is the oxidation number of H not +1?

Answer 15

it is -1 in metal hydrides

Question 16

Why is the oxidation number of fluorine always -1?

Answer 16

because fluorine is the most electronegative element so no other element can remove an electron from fluorine

Question 17

What is the oxidation number of group 1 metals?

Answer 17

always +1

Question 18

What is the oxidation number of group 2 metals?

Answer 18

always +2

Question 19

What is the oxidation number of aluminium?

Answer 19

+3