Chapter 1: Atomic Structure

Question 1

What is the relative charge and mass of a electron?

Answer 1

Charge= -1
Mass= 1/1840

Question 2

What is an isotope?

Answer 2

2 or more forms of the same element with the same number of protons and electrons but different number of neutrons.

Question 3

What is the definition of the first ionisation energy?

Answer 3

Energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous +1 ions.

Question 4

What are the 3 factors that affect ionisation energy?

Answer 4

1. Atomic radius
2. Shielding by inner electrons
3. Size of the positive nucleus charge

Question 5

What is the TOF mass spectrometry used for?

Answer 5

1. Find the abundance and mass of each isotope in an element which allows us to find the relative atomic mass
2. Find the relative molecular mass of substances made of molecules

Question 6

Explain the process of electron ionisation

Answer 6

1. An electron gun fires high energy electrons at the sample.
2. This knocks off an electron from each particle which then forms +1 ions
3. The +1 ions are attracted to the negatively charged plate and are accelerated using an electric field. (So that they all have the same kinetic energy)
4. The lighter ions travel through faster and hit the detector quicker.
5. When the +1 ions hit the detector they create a current.

Question 7

What is the formula to calculate kinetic energy?

Answer 7

KE=1/2MV^2

Question 8

How do you workout the time along the flight tube?

Answer 8

Time=distance/velocity