Redox

Question 1

oxidation number/state

Answer 1

oxidation number of an element is a measure of the number of electrons that an atom uses to bond with atoms of another element

Question 2

ON of potassium fluoride

Answer 2

F = +1
K = -1

Question 3

ON of sulfur dioxide

Answer 3

S = +4
O = -2

Question 4

ON of bromine

Answer 4

Br = 0 because not forming bonds with atoms of a different element

Question 5

how should you give oxidation numbers

Answer 5

always give oxidation ion number of each ion

Question 6

sum of all ON in a neutral compound is

Answer 6

0

Question 7

sum of all ON in an ion is equal to the

Answer 7

charge on that ion

Question 8

ON of any uncombined element e.g H2, Br2 is

Answer 8

0

Question 9

ON of oxygen in compounds is

Answer 9

-2

Question 10

EXCEPTION - ON of oxygen in peroxides e.g H2O2 is

Answer 10

-1

Question 11

ON of hydrogen in a compound is

Answer 11

+1

Question 12

EXCEPTION - ON of hydrogen in hydrides e.g LiH is

Answer 12

-1

Question 13

in compound group 1 element has ON of

Answer 13

+1

Question 14

in compound group 2 element has ON of

Answer 14

+2

Question 15

in compound group 3 element has ON of

Answer 15

+3

Question 16

group 7 element can have different ON so assume On is

Answer 16

-1

Question 17

oxyanions are

Answer 17

negative ions consisting of oxygen and one or more elements and usually end in ‘ate’

Question 18

redox

Answer 18

reaction where both oxidation and reduction take place

Question 19

oxidation

Answer 19

loss of electrons/an increase in ON number

Question 20

reduction

Answer 20

gain of electrons/a decrease in ON number

Question 21

how to determine if a reaction is redox

Answer 21

1. changes in ON of an element
2. transfer of electrons to/from an element

Question 22

oxidising agent

Answer 22

reagent that oxidises (takes electrons from) another species

Question 23

reducing agent

Answer 23

reagent that (adds electrons to) another species