Wrong Anwsers

Question 1

Deduce the formula of the compound that contains 2+ ions and 3- ions that both have the same electron configuration as argon.

Answer 1

Ca3P2

Question 2

Deduce which of Na+ and Mg2+ is the smaller ion.
Explain your answer.

Answer 2

Mg2+
Because it has the more protons with the same amount of shielding

Question 3

Explain why the first ionisation energy of sulfur is different from that of phosphorus

Answer 3

E- paired in the 3p orbital in S and
paired e- repel more so less energy is required to remove electrons

Question 4

Using the same apparatus, suggest how the procedure could be improved to reduce the percentage uncertainty in using the burette.
Justify your suggested improvement.

Answer 4

Use a larger mass of the solid
So there would be a larger titrate value which will decrease uncertainty

Question 5

In terms of structure and bonding explain why the boiling point of bromine is
different from that of magnesium. Suggest why magnesium is a liquid over a much greater temperature range compared to bromine.

Answer 5

M1 Bromine is simple molecules

M2 Magnesium is metallic

M3 Br2 has weak IMFs

M4 so more energy is needed to overcome the stronger metallic bonds

M5 molten mg is stronger

Question 6

Explain how ions are accelerated, detected and have their abundance determined in a time of flight TOF mass spectrometer

Answer 6

(lons accelerated by) attraction to negatively charged plate / electric field
Ions detected by gaining electrons
Abundance determined by (size) of current flowing (or amount of electrons gained) in the detector

Question 7

Name the type of bond formed between N and Al in H3NAlCl3 and explain how
this bond is formed.

Answer 7

Dative (covalent) /co-ordinate bond

Shared pair of / both electrons come from the N(H3)

Question 8

Explain how the value of the Cl-Al-Cl bond angle in ACl3 changes, if at all, on formation of the compound H3NAICl3

Answer 8

Aluminium is now surrounded by 4 electron pairs/bonds or is tetrahedral

Therefore Cl-Al-Cl bond angle decreases / changes (from 120° in AlCls ) to allow range 107-111° in H3NAICl3

Question 9

Half equations for oxidation of chlorine ions

Answer 9

2Cl- —> Cl2 + 2e-

Question 10

Half equations for reduction of chlorite (I) ions to chlorine in acidic conditions

Answer 10

2ClO- + H+ 2e- —> Cl2 + 2H2O