2.1 Definitions

Question 1

Atomic number

Answer 1

The number of protons in the nucleus of the atom

Question 2

Bohr Model

Answer 2

Describes an atom as a small dense nucleus with electrons orbiting around the nucleus. This model explains different periodic properties of atoms.

Question 3

Electron

Answer 3

A negatively-charged subatomic particle which orbits the nucleus at various energy levels. The relative atomic mass of an electron is 1/1836

Question 4

Ion

Answer 4

A charged atom or molecule

Question 5

Isotopes

Answer 5

Atoms of the same element with the same number of protons and electrons but different numbers of neutrons, isotopes of an element have different masses

Question 6

Mass number

Answer 6

The total number of protons and neutrons in the nucleus of an atom

Question 7

Mass spectrometry

Answer 7

An instrument which gives accurate information about relative isotopic ,ass and the relative abundance of isotopes

Question 8

Neutron

Answer 8

A neutral subatomic particle found in the nucleus of an atom. The relative mass of neutron is 1.

Question 9

Proton

Answer 9

A positively charged charged subatomic particle found in the nucleus of an atom. The relative mass is 1.

Question 10

Relative abundance

Answer 10

The amount of one substance compared with another

Question 11

Relative atomic mass

Answer 11

The weighted mean mass of an atom compared with 1/12th mass of an atom of carbon-12

Question 12

Relative isotopic mass

Answer 12

The mass of an atom of an isotope compared with 1/12th mass of an atom of carbon-12

Question 13

Relative formula mass

Answer 13

The mass of the formula unit of a compound with a giant structure. For example NaCl has a relative formula mass of 58.44 g mol.

Question 14

Relative molecular mass

Answer 14

The mass of a simple molecule