2.1.1: Atomic structure

Question 1

Ion

Answer 1

A charged particle; an atom that has gained/lost electrons.

Question 2

Relative formula mass (not required)

Answer 2

The number of times the mean mass of one molecule of the molecular compound is heavier than 1/12.0, the mass of one atom of carbon-12.

Question 3

Relative atomic mass (Aᵣ)

Answer 3

The weighted mean mass of an atom of an element relative to 1/12th the mass of an atom of carbon-12.

Question 4

Relative isotopic mass

Answer 4

The mass of an isotope relative to 1/12th the mass of an atom of carbon-12.

Question 5

Degenerate

Answer 5

having the same energy

Question 6

Orbital

Answer 6

A probability region for an electron.

Question 7

First ionisation energy

Answer 7

The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous unipositive cations.

Question 8

Positive ion

Answer 8

Cation

Question 9

Negative ion

Answer 9

Anion

Question 10

Electron relative mass

Answer 10

1/1840

Question 11

Neutron relative mass

Answer 11

1

Question 12

Proton relative mass

Answer 12

1

Question 13

Uses of Mass Spectrometry

Answer 13

• Determination of (relative masses/abundances of) isotopes
• Determination of successive ionisation energies
• Determination of molecular structure

Question 14

Mass Spectrometry steps

Answer 14

1) Vaporise sample
2) Ionise sample
3) Accelerate sample
4) Deflect through magnetic field according to mass/charge ratio
5) Detect the ions

Question 15

Why is the ‘charge’ in the mass-charge ratio always the same?

Answer 15

• Electron gun knocks out outermost electron
• Therefore the charge is always +1
• So the mass determines the deflection

Question 16

Isotopes

Answer 16

Atoms of the same element with the same number of protons and electrons but different numbers of neutrons and thus different masses.

Question 17

Difference between ‘relative formula mass’ and ‘relative molecular mass’

Answer 17

• RFM: refers to compounds with giant structure

* RMM: refers to simple molecules

Question 18

How to calculate RFM or RMM

Answer 18

(No. of atoms of element x Aᵣ of element) + (No. of atoms of element x Aᵣ of element) continue as necessary

Question 19

How to calculate Aᵣ from relative isotopic abundance

Answer 19

(Mass number x abundance %) + (Mass number x abundance %)