Definitions

Question 1

Define covalent bond.

Answer 1

The electrostatic attraction between a shared pair of electrons and the nuclei of two bonded atoms.

Question 2

Define lone pair.

Answer 2

A pair of unshared electrons in the outer shell of an atom.

Question 3

Define coordinate (Dative) bond.

Answer 3

A shared pair of electrons between two atoms with both electrons shared by one atom.

Question 4

Define octet rule.

Answer 4

When forming a compound, an atom tends to gain, lose or share electrons to achieve eight in its outer shell.

Question 5

Define electronegativity.

Answer 5

The extent to which an atom attracts the bonding electrons in a covalent bond.

Question 6

Define Polar bond.

Answer 6

A covalent bond in which there is unequal sharing of the bonding electrons.

Question 7

Define delocalised electrons.

Answer 7

Outer electrons do not have fixed positions but move freely.

Question 8

Disproportionation

Answer 8

Oxidation and reduction in he same species in the same reaction.

Question 9

Avogadro’s number.

Answer 9

Number of atoms in 12.000g of carbon 12.

Question 10

Mole

Answer 10

The amount of substance which contains the Avogadro number of atoms, molecules or groups of ions.

Question 11

Molar mass.

Answer 11

The mass of one mole of a substance.

Question 12

Anhydrous.

Answer 12

A salt which contains no water of crystallisation.

Question 13

Hydrated.

Answer 13

A salt which contains water of crystallisation

Question 14

Water of crystallisation.

Answer 14

Water chemically bonded within a crystal structure.

Question 15

Intermolecular

Answer 15

Between neighbouring molecules.

Question 16

Van der Waals forces

Answer 16

The attraction between instantaneous and induced dipoles of neighbouring molecules.

Question 17

Permanent dipole dipole attraction.

Answer 17

Attraction between the positive end, +, of the permenant dipole on a molecule with a permanent negative dipole, of a neighbouring molecule.

Question 18

Hydrogen bond

Answer 18

The attraction between a lone pair of electrons on a very electronegative molecules (N, O, F) on one molecule and a hydrogen on a neighbouring molecule, in which the hydrogen is covalently bonded to a very electronegative atom.

Question 19

Lone pair.

Answer 19

A pair of unshared electrons in the outer shell of an atom.

Question 20

Atomic number.

Answer 20

The number of protons in the nucleus of an atom.

Question 21

Mass number.

Answer 21

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

Question 22

Relative atomic mass.

Answer 22

The average mass of an atom of an element relative to one twelfth of the mass of and atom of carbon 12.

Question 23

Relative isotopic mass.

Answer 23

The mass of an atom of an isotope of an element relative to one twelfth of the mass of an atom of carbon 12.

Question 24

Isotopes.

Answer 24

Atoms which have the same atomic number but a different mass number.

Question 25

Relative molecular mass.

Answer 25

The average mass of a molecule relative to one twelfth of an atom of carbon 12.

Question 26

Molecular ion.

Answer 26

When there are two or more ions covalently bonded with an overall charge.

Question 27

First ionisation energy.

Answer 27

The energy required to convert one mole of gaseous atoms into gaseous ions with a single positive charge.

Question 28

Second ionisation energy.

Answer 28

The energy required to convert one mole of gaseous ions with a single positive charge into gaseous ions with a double positive charge.

Question 29

Third ionisation energy.

Answer 29

The energy required to convert one mole of gaseous ions with a double positive charge into gaseous ions with a triple positive charge.

Question 30

Relative formula mass.

Answer 30

The average mass of a formula unit relative to that of one twelfth of carbon 12.

Question 31

Oxidising agent

Answer 31

Electron acceptor.

Question 32

Reducing agent.

Answer 32

Electron donor.

Question 33

Strong acid/base.

Answer 33

An acid/base that fully dissociates in water.

Question 34

Weak acid/base.

Answer 34

Partially dissociates in water

Question 35

Oxidation.

Answer 35

Loss of electrons/increase in oxidation state.

Question 36

Molarity.

Answer 36

Concentration in mol/dm3 expressed using M.

Question 37

Concentration.

Answer 37

Number of moles or mass present in a stated volume.

Question 38

Standard solution.

Answer 38

A solution for which the concentration is known.

Question 39

Orbital

Answer 39

A region within an atom that can hold up to two electrons with opposite spins.

Question 40

Ionic bonding.

Answer 40

The electrostatic force of attraction between oppositely charged ions formed by electron transfer.

Question 41

Bond polarity.

Answer 41

Arises when covalently bonded atoms have different have different electronegativity values and partial charges + and - are formed within the bond.