Key Terms

Question 1

Relative atomic mass

Answer 1

(Ar) The average mass of an atom of an element relative to 1/12th of the mass of an atom of the isotope carbon-12.

Question 2

Isotope

Answer 2

Atoms of the same element that have the same number of protons but a different number of neutrons. So same atomic number different mass number.

Question 3

Giant structures

Answer 3

Crystal structures in which all the atoms or ions are linked by a network of strong bonding extending throughout the crystal.

Question 4

Simple molecular structures

Answer 4

Consists of groups of atoms held together by strong covalent bonding within the molecules, but with weak forces of attraction between the molecules.

Question 5

Intermolecular forces

Answer 5

Weak attractive forces between molecules.

Question 6

Covalent bond

Answer 6

Strong electrostatic attraction between two nuclei and the shared pair of electrons between them.

Question 7

Lone pair

Answer 7

Pair of electrons in the outer shell of one of the atoms in a molecule or ion which is not involved in bonding.

Question 8

Dative covalent bond

Answer 8

Two atoms share a pair of electrons, both the electrons are being donated by one atom.

Question 9

First ionisation energy

Answer 9

The emergency needed to remove one mole (one electron) of electrons from one mole of gaseous atoms or ions of an element.

Question 10

Oxidation number

Answer 10

Distinguishes between the compounds of elements that can exist in more than one oxidation state.

Question 11

Empirical formula

Answer 11

Shows the simplest whole number ratio of different elements in a compound.

Question 12

Molecular formula

Answer 12

Gives the actual number of atoms of each element in a molecule.

Question 13

Successive ionisation energies

Answer 13

Happens each time an electron is removes form an atom, molecule or ion.

Question 14

Relative isotopic mass

Answer 14

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