Atomic Structure

Question 1

Name the two sub-atomic particles present in the nucleus, giving their charges

Answer 1

Protons (positive) and neutrons (no charge)

Question 2

What are the four stages in a mass spectrometer?

Answer 2

Ionisation, acceleration, deflection and detection

Question 3

What occurs during ionisation?

Answer 3

The vapourised sample is bombared by high energy electrons from an electron gun, knocking out an electron from the sample, forming a cation

Question 4

What occurs during acceleration?

Answer 4

The cation is passed between negatively electrically charged plates, accelerating it onwards at high velocity

Question 5

What occurs during deflection?

Answer 5

The cation passes through an electromagnet, which causes the ion to deflect. The degree of deflection and m/z ratio are inversely proportional

Question 6

What occurs during detection?

Answer 6

The samples bombard the detector plate, causing an electrical signal. The more frequent the bombardments the more intense the signal.

Question 7

Define the term “relative atomic mass”

Answer 7

The mass of an atom of an element taking into account all of its isotopes relative to 1/12th of the mass of an atom of 12C

Question 8

Give the electronic configuration for titanium

Answer 8

1s(2) 2s(2) 2p(6) 3s(2) 3p(6) 3d(2) 4s(2)

Question 9

What is the maximum number of electrons allowed in a d sub-orbital?

Answer 9

10

Question 10

What is an isotope?

Answer 10

An element whose atoms contain a variable amount of neutrons, e.g. 35Cl and 37Cl