Atomic Structure Exam Questions

Question 1

State and explain the block in the periodic table in which sulphar is placed

Answer 1

D block because it has 3 orbitals

Question 2

Explain why chromium is placed in d block

Answer 2

It has the highest energy

Question 3

Recipe for state and explain the general trend in first ionisation energies

Answer 3

Proton number
Neuclar charge
Shielding

Question 4

State the meaning of the term mass number of an isotope

Answer 4

Total number of protons and neutrons

Question 5

State the two measurements that are recorded for each isotope

Answer 5

M/Z
Relative abundance

Question 6

State why isotopes of an element have the same chemical properties

Answer 6

Same number of electrons

Question 7

Define the term relative atomic mass

Answer 7

The total mass of an element that is measured by the average relatively of a 1/12 of a carbon 12 atom

Question 8

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

Answer 8

Si is in a higher energy level so there is more shielding so require less energy to remove an electron

Question 9

State and explain the trend in atomic radius of the period 3 elements from sodium to chlorine

Answer 9

Decrease as there similar shielding but there an increase in neuclar charge as proton number increase by 1

Question 10

state how krypton is ionised in the mass spectrometer (that how u know its electrospray ionisation plus its a 5 marker)
and sometimes the mass spectrum of kr has a very small peak with an m/z value of 42. Explain the occurrence of this peak

Answer 10

dissolved in solvent and injected through a needle
then the sample is connected to + terminal of high voltage power supply this allows the sample to lose 2 electron and form a plus 2 positive ion

Question 11

in period 3 explain how the position of sulphur and aluminium differ from the general trend

Answer 11

aluminium= its on a higher energy level so it further away from the nucleus so less IE is required

sulphur= there’s an extra electrons in the 3p orbital so the a repulsion between the pair of electrons so less IE is required as its easier to remove
* have to be specific with the orbital

Question 12

suggest why the first ionisation energy of krypton is lower than the first ionisation energy of argon

Answer 12

krypton has more shielding so there is a decrease in ionisation energy needed