Definitions

Question 1

Avagadro’s constant

Answer 1

number of atoms per mole of the carbon-12 isotope

Question 2

Covalent bond

Answer 2

bond formed by a shared pair of electrons by 2 non-metals

Question 3

dative covalent bond

Answer 3

bond formed by a shared pair of electrons that has been provided by one of the bonding atoms only

Question 4

electronegativity

Answer 4

a measure of the attraction of an electron in a covalent bond

Question 5

empirical formulae

Answer 5

simplest whole number ratio of atoms of each element present in a compound (eg c4h8 = ch2)

Question 6

first ionisation energy

Answer 6

energy required to remove one electron from each atom in a mole of gaseous atoms

Question 7

hydrogen bond

Answer 7

strong permanent dipole- permanent dipole attraction between an electron deficient hydrogen atom

Question 8

ionic bond

Answer 8

electrostatic attraction between oppositely charged ions

Question 9

london dispersion forces

Answer 9

attractive forces between induced dipoles in neighbouring molecules

Question 10

metallic bonding

Answer 10

electrostatic attraction between cations and delocalised electrons

Question 11

relative atomic mass

Answer 11

weighted mean mass of an atom of an element compared with 1/12 of the mass of carbon-12

Question 12

relative isotopic mass

Answer 12

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

Question 13

van der waals forces

Answer 13

intermolecular bonding that includes permanent dipole-dipole interactions