Definitiona

Question 1

Atomic number

Answer 1

Number of protons in the nucleus of each atom in an element

Question 2

Nucleon number

Answer 2

Total number of protons and neutrons in an atom

Question 3

Isotopes

Answer 3

Atom of the same element with the same number of protons but a different number of neutrons

Question 4

First ionization energy

Answer 4

Energy required to remove one mole of electrons from one mole of gaseous atom to form one mole of 1+ ions under standard conditions

Question 5

Relative atomic mass

Answer 5

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

Question 6

Relative molecular mass

Answer 6

the weighted average mass of one molecule of an element or compound compared with 1/12 of the mass of an atom of carbon-12

Question 7

Relative isotopic mass

Answer 7

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

Question 8

Relative formula mass

Answer 8

the mass of one mole of a compound compared with 1/12 of the mass of an atom of carbon-12

Question 9

Mole

Answer 9

amount of substance containing NA=6.02*1023 of particles/molecules/atoms

Question 10

Unified atomic mass

Answer 10

One twelfth of the mass of a carbon 12 atom

Question 11

Empirical formula

Answer 11

The simplest whole number ratio of atoms of each element in a compound

Question 12

Molecular formula

Answer 12

the actual number of atoms of each element in a compound

Question 14

Electronegativity

Answer 14

power of an atom to attract electrons to itself

Question 15

Ionic bonding

Answer 15

electrostatic attraction between oppositely charged ions

Question 16

Metallic bonding

Answer 16

electrostatic attraction between positive metal ions and delocalised electrons

Question 17

Covalent bonding

Answer 17

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

Question 18

Bond energy

Answer 18

energy required to break one mole of a particular covalent bond in the gaseous state

Question 19

Bond length

Answer 19

internuclear distance of two covalently bonded atoms

Question 20

Enthalphy of formation

Answer 20

enthalpy change when one mole of a compound is formed from its (constituents) elements in their standard states

Question 21

Enthalpy of neutralisation

Answer 21

enthalpy change when 1 mole of water is formed from an (aqueous) acid and an alkali under standard conditions

Question 22

Enthalpy of combustion

Answer 22

enthalpy change when one mole of element/compound is completely combusted (excess O2) under standard conditions

Question 23

Oxidising agent

Answer 23

a species that accept electrons

Question 24

Reducing agent

Answer 24

a species that donates electrons

Question 25

Dynamic equillibrium

Answer 25

rate of forward= rate of backward reactions in closed system concentration of reactants and products remaining constant

Question 26

Le Chatelier’s principle

Answer 26

If a change is made to a system at dynamic equilibrium, the position of equilibrium moves to minimise this change

Question 27

Hydrocarbons

Answer 27

compound made up of C and H atoms only

Question 28

Free radicals

Answer 28

species with one or more unpaired electrons

Question 29

Structural isomers

Answer 29

molecules that have same molecular formula but different structural formulae

Question 30

Stereoisomerism

Answer 30

molecules that have same molecular formula and same structural formula but different arrangement of atoms in space