ie exam qs

Question 1

State and explain the trend in the first ionisation energies of the elements in Group
2 from magnesium to barium.

Answer 1

decreases, ions get bigger, weaker attraction of ion to lost electron

Question 2

State the element in Period 3 that has the highest first ionisation energy.
Explain your answer

Answer 2

Argon, largest number of protons same amount of shielding

Question 3

Give one reason why the second ionisation energy of silicon is lower than the
second ionisation energy of aluminium.

Answer 3

Electron in Si (removed from) (3)p orbital

Question 4

Explain why the ionisation energy of every element is endothermic.

Answer 4

Heat or energy needed to overcome the attraction between the negative electron and the positive nucleus

Question 5

Explain why the value of the first ionisation energy of sulfur is less than the value of
the first ionisation energy of phosphorus.

Answer 5

Paired electrons in (3)p orbital
repel

Question 6

Explain why the second ionisation energy of magnesium is greater than the
first ionisation energy of magnesium.

Answer 6

electron being removed is closer to the nucleus

Question 7

Explain why the first ionisation energy of sulphur is lower than would be
predicted from the general trend.

Answer 7

e–pair in the 3p sub-level
repulsion between the e–
in this e–pair

Question 8

Explain why the value of the first ionisation energy of magnesium is higher than that
of sodium.

Answer 8

more protons, same shielding

Question 9

How the values deviate from the trend
Explanation for Al
Explanation for S

Answer 9

How values deviate from trend: (both values) too low
Explanation for Al: e– removed from (3) p
Explanation for S: e– removed from (3)p electron pair repulsion between paired e–

Question 10

Explain why chromium is placed in the d block in the Periodic Table.

Answer 10

Highest energy e

Question 11

Explain the general increase in the values of the first ionisation energies of the
elements Na–Ar

Answer 11

increased nuclear charge, same shielding, Stronger attraction between nucleus and outer electrons

Question 12

for describing electron spray ionisation

Answer 12

say particle gains a proton

Question 13

Give the formula of the ion that reaches the detector first in the TOF mass
spectrometer.

Answer 13

C3H6O2N+

Question 14

cm to m

Answer 14

/100

Question 15

Explain why the first ionisation energy of the Group 2 elements decreases down the
group

Answer 15

the atoms get larger
There is a weaker attraction between the nucleus and the outer
electron