1.1 Exam Questions

Question 1

State two features of the current model that are not shown in the Rutherford model. [2]

Answer 1

Current model includes neutrons and protons
Current model shows elections in different energy levels

Question 2

What is the general equation for electrospray ionisation? [1]

Answer 2

X(g) + H+ → XH+ (g)

Question 3

Define the mass number of an atom. [1]

Answer 3

Number of protons and neutrons in the nucleus of an atom

Question 4

Define the term relative atomic mass. [2]

Answer 4

The average mass an of atom of an element
On a scale in which the mass of an atom of carbon-12 is 1

Question 5

Describe how molecules are ionised using electrospray ionisation. [3]

Answer 5

Sample is dissolved in a volatile solvent
Injected through a needle at a high voltage
So each molecule gains a proton

Question 6

State two differences between the plum pudding model and the model of atomic structure used today. [2]

Answer 6

Nucleus contains protons and neutrons
Electrons are arranged in energy levels

Question 7

Describe how ions are formed in a TOF mass spectrometer. [2]

Answer 7

A high voltage is applied to a sample in a polar solvent
So sample gains a proton

Question 8

Explain why it is necessary to ionise molecules when measuring their mass in a TOF mass spectrometer. [2]

Answer 8

Ions will be accelerated by an electric field
Only ions will create a current when hitting the detector