AS Chemistry Definitions List 1

Question 1

Atomic number

Answer 1

Number of protons in one atom or nucleus

Question 2

Mass number

Answer 2

Number of protons and neutrons in the nucleus of an atom

Question 3

Isotope

Answer 3

Atoms with the same number of protons but different numbers of neutrons

Question 4

Relative atomic mass

Answer 4

Average mass of atom of an element

1/12 mass of one atom 12C

Question 5

Relative molecular mass

Answer 5

Average mass of a molecule

1/12 mass of atom of 12C

Question 6

Ions

Answer 6

+ve or -be charged atoms that have lost/ gained electrons

Question 7

Why do isotopes of an element have similar chemical properties?

Answer 7

The have the same number of electrons on their outer shells