topic 3

Question 1

what is meant my oxidation number

Answer 1

a number assigned to an element which represents the number of electrons lost or gained by an atom of an element in the compound

Question 2

how do metal ions form in general

Answer 2

forms positive ions through loss of electrons with an increase in oxidation number

Question 3

what do non metals in general form

Answer 3

they form negative ions by gain of electrons with a decrease in oxidation number

Question 4

how do you construct half equations

Answer 4

show how many electrons are being lost or gained
e.g Al 3 + + 3e - → Al
2Cl - → Cl 2 + 2e -

Question 5

how to construct full ionic equations from half ionic equations

Answer 5

1) write the half ionic equations and make sure theyre balanced by adding electrons, water or hydrogen ions
2) multiply the half equations to get the same number of electrons in both of the half equations
3) combine the half equations and cancel out things that are the same