Atomic Structure

Question 1

What are the relative charges of a proton, neutron and electron

Answer 1

Proton = +1
Neutron = 0
Electron = -1

Question 2

What are the relative masses of a proton, neutron and electron

Answer 2

Proton = 1
Neutron = 1
Electron = 1/
1840

Question 3

What does an atom consist of?

Answer 3

A nucleus containing protons and neutrons surrounded by electrons

Question 4

Mass number

Answer 4

Number of protons + number of neutrons

Question 5

Atomic number

Answer 5

Number of protons

Question 6

What is an isotope

Answer 6

Same number of protons but different numbers of neutrons

Question 7

Do isotopes react in the same way or differently to their atom

Answer 7

The same way as same electron configuration

Question 8

How do you do mass spectrometry

Answer 8

Electrospray - sample is dissolved in volatile solvent and forced through a fine hollow needle that is connected to a high voltage. This causes the samples to gain a proton

Electron impact - sample is vaporised and high energy electrons are fired at it from an electron gun knocking off an electron in the process

Accelerated by a negatively charged plate, becomes a beam of ionised molecules travelling along the flight tube (Ion drift), reach detector and cause a current to flow (detection). Time of flight used to work out m/z value and plot graph (data analysis).

Question 9

What information does a mass spectrometer give

Answer 9

The mass spectrometer gives accurate information about relative isotopic mass and also about the relative abundance of isotopes.

Question 10

What is mass spectrometry used for?

Answer 10

To identify elements or Relative molecular mass

Question 11

What is are the different types of orbital

Answer 11

S, P, D, F

Question 12

How do electrons fill up

Answer 12

Atomic orbitals of the same energy fill singly before pairing starts because electrons repel each other

Question 13

How many electrons can an orbital hold?

Answer 13

2

Question 14

What is ionisation energy?

Answer 14

The energy required to remove one mole of electrons from one mole of gaseous atoms under standard conditions and states

Question 15

Does ionisation energy increase or decrease along a period

Answer 15

Increases as shielding remains the same but there is an increase in nuclear charge. It may drop between certain elements of it moves into the next orbital up

Question 16

Why is there a decrease in ionisation energy between phosphorous and Sulphur

Answer 16

Sulphur has 1 electron paired up and 2 not whereas Phosphorous has 3 unpaired. The repulsion of the pair makes it easier to remove

Question 17

How does ionisation energy change down a group

Answer 17

It decreases due to increased shielding, even though there is a higher nuclear charge

Question 18

Why do isotopes exist

Answer 18

Instability in an atoms

Question 19

Electron spray equation vs Electron impact equation

Answer 19

Spray: X + H+ —> XH+
Impact: X —> X+ + e-

Question 20

Electron impact vs Electro spray
What’s used for what

Answer 20

Impact is used for substances with low Mr’s as it causes larger molecules to fragment

Question 21

What is fragmentation

Answer 21

A larger molecules is split into smaller molecules and ions

Question 22

How does a mass spectrometer detect ions?

Answer 22

The ions create a current on the detector plate