Chemistry Revision 3

Electronic configurations

State which block in the periodic table you find the following elements:

Sulphur Vanadium Strontium

Electronic configurations

Sulphur = p Vanadium = d Strontium = s Write the full electronic configurations of

the following elements (in terms of 1s2 etc) Chlorine (17e), Cobalt (27e), Copper (29e)

Electronic configurations

Chlorine 1s2 2s2 2p6 3s2 3p5

Cobalt 1s2 2s2 2p6 3s2 3p6 3d7 4s2

Copper 1s2 2s2 2p6 3s2 3p6 3d10 4s1

Note this is an exception along with CHROMIUM

Group 7 Chemistry

Complete the following table

Halogen Colour at 298K

State at 298K

Fluorine

Chlorine

Bromine

Iodine

More on group 7

What do I see if I add sodium bromide solution to a solution of silver nitrate?

Write the IONIC equation for this reaction, including state symbols.

The answer-

A cream precipitate would form on mixing the two colourless solutions.

Ag+ (aq) + Br- (aq) AgBr (s)

Remember that an ionic equation does not include spectator ions!!

Oxidation numbers

Identify oxidation numbers in the following, and thus deduce whether it is oxidation or reduction or neither!

Start End Ox? red?

Br2 KBr

KMnO4 Mn2+

AgNO3 AgI

Fe2+ Fe3+

NH3 NO2

And the answers

Start End

Br2 0 KBr -1 Reduction

KMnO4 +7 Mn2+ +2 Reduction

AgNO3 +1 AgI +1 Neither

Fe2+ +2 Fe3+ +3 Oxidation

NH3 -3 NO2 +4 Oxidation

Half equations

Write the overall equation and the two half equations for the reactions occurring when chlorine water is added to potassium iodide solution

Identify what has been reduced.

Half equations

Cl2 (aq) + 2I- (aq) 2Cl- (aq) + I2 (aq)

Reduced: Cl2 (aq) + 2e- 2Cl- (aq)

Oxidised: 2I- (aq) 2e- + I2 (aq)

Remember half equations do as they say- they show what is happening in half the equation!

Economic importance of Cl + Br

Give 2 uses of chlorine or its compounds Give 2 uses of bromine or its compounds

Remember you are expected to know the redox chemistry of the extraction of bromine from sea water.

Ionic Lattices

Draw a labelled diagram to show the structure of an ionic lattice, as exemplified by sodium chloride

Solution calculations

It takes 12.30cm3 of 0.05M NaOH to neutralise 25.00cm3 of HCl.

1) Write the balanced chemical equation 2) Work out the number of moles of NaOH

used 3) Work out the concentration of HCl

Now try the exam q.

More next week. Remember- I am here to help and support-

BUT I can’t do the work for you. Are you “striving for the best of yourself

always”??