FC12: Oxidation States

Question 1

What is oxidation

Answer 1

loss of electrons, gain of oxygen

Question 2

What is reduction

Answer 2

gain of electrons, loss of oxygen

Question 3

What does an increase/decrease in oxidation number mean?

Answer 3

oxidation/reduction

Question 4

What oxidation number do uncombined elements have

Answer 4

zero

Question 5

what oxidation number do monatomic ions have

Answer 5

same size and sign as the charge of the ion

Question 6

What is the fixed O.N. of combined hydrogen

Answer 6

+1, except in hydrides where it is -1

Question 7

What is the fixed O.N. of combined oxygen

Answer 7

-2, except in peroxides where it is -1, when bonded to F where it is +2

Question 8

What is the fixed O.N. of group 1 elements in compounds

Answer 8

+1 usually

Question 9

What is the fixed O.N. of fluorine

Answer 9

-1 usually

Question 10

What must the sum of the O.N.s in a formula equal

Answer 10

the charge of the formula

Question 11

What does the roman numeral immediately after the part of the compound’s name mean?

Answer 11

The O.N. of the element that can have a variable O.N.

Question 12

When given the systematic name of a polyatomic ion, and you need to work out the formula, what sign must the sum of the O.N.s for the formula to be correct for atoms

Answer 12

negative

Question 13

write out a half equation for sodium being oxidised from an ON of 0 to and ON of +1

Answer 13

Na -> Na+ + e-

Question 14

What is a redox reaction

Answer 14

When the reactants undergo a change in their oxidation states in a reaction