Key Terms Unit 1

Question 1

Oxidation Number

Answer 1

Is the number of electrons that need to be added to or removed from an element to make it neutral

Question 2

Atomic Number

Answer 2

Is the number of protons in the nucleus of an atom

Question 3

Mass Number

Answer 3

Is the number of protons and neutrons in the nucleus of an atom

Question 4

Isotopes

Answer 4

Are atoms that have the same number of protons but different numbers of neutrons

Question 5

Ion

Answer 5

Is a particle where the number of electrons does not equal the number of protons

Question 6

α - particles

Answer 6

Have a nucleus of two protons and two neutrons, therefore positively charged

Question 7

β - particles

Answer 7

Are fast moving electrons, therefore negatively charged

Question 8

γ - rays

Answer 8

Are high energy electromagnetic radiation, therefore no charge

Question 9

Half-life

Answer 9

Is the time taken for the atoms in a radioisotope to decay, or the time take for the radioactivity of a radioisotope to fall to half its initial value

Question 10

Atomic orbital

Answer 10

Is a region in an atom that can hold up to two electrons with opposite spins

Question 11

First Ionisation Energy

Answer 11

Is the energy required to remove one electron from each atom in one mole of its gaseous atoms

Question 12

Shielding Effect

Answer 12

Is the repulsion between electrons in different shells. Inner shell electrons repel outer shell electrons

Question 13

Successive Ionisation Energies

Answer 13

Are a measure of the energy need to remove each electron in turn until all the electrons are removed from an atom

Question 14

Convergence Limit

Answer 14

Is when spectral lines become so close together they have continuous band of radiation and separate lines cannot be distinguished

Question 15

Relative Atomic Mass

Answer 15

Is the average mass of one atom of the element relative to one-twelfth the mass of one atom of carbon-12

Question 16

Relative Isotopic Mass

Answer 16

Is the mass of an atom of an isotope relative to one-twelfth the mass of an atom of carbon-12

Question 17

Relative Formula Mass

Answer 17

Is the sum of the relative atomic masses of all atoms present in the formula

Question 18

Molecular Ion

Answer 18

Is a positive ion formed in a mass spectrometer from the whole molecule

Question 19

Fragmentation

Answer 19

Is splitting of molecules, in a mass spectrometer into smaller parts

Question 20

One Mole

Answer 20

Is the amount of any substance that contains the same number of particles as there are atoms in 12g of carbon-12

Question 21

Avogadro Constant

Answer 21

Is the number of atoms per mole

Question 22

Molar Mass

Answer 22

Is the mass of one mole of a substance

Question 23

Stoichiometry

Answer 23

Is the molar relationship between the amounts of reactants and products in a chemical reaction

Question 24

Empirical Formula

Answer 24

Is the simplest formula showing the simplest whole number ratio of the number of atoms of each element present

Question 25

Molecular Formula

Answer 25

Shows the actual number of atoms of each element present in the molecule it is a simple multiple of the empirical formula

Question 26

Molar Volume, V_m

Answer 26

Is the volume per mole of a gas, (given on data sheet)

Question 27

Atom Economy

Answer 27

Is the percentage of Mass of reactants divided by total mass of reactants

Question 28

Percentage Yeild

Answer 28

Is the percentage of Mass of product obtained divided by Maximum theoretic mass

Question 29

Ionic Bond

Answer 29

Is a bond formed by the electrical attraction between positive and negative ions

Question 30

Covalent Bond

Answer 30

Has a pair of electrons with opposed spin shared between two atoms with each atom giving one electron

Question 31

Coordinate Bond

Answer 31

Is a covalent bond in which both electrons are shared by one of the atoms

Question 32

Electronegativity

Answer 32

Is a measure of the electron-attracting power of an atom in a covalent bond

Question 33

Polar Bond

Answer 33

Has one end of the bond with a slightly positive charge and the other end with a slightly negative charge

Question 34

Intermolecular Bonding

Answer 34

Is the weak bonding holding the molecules together, and governs the physical properties of the substance

Question 35

Intramolecular Bonding

Answer 35

Is the strong bonding between atoms in the molecule, and governs its chemistry

Question 36

Van Der Waals Forces

Answer 36

Include all types of intermolecular force whether dipole or induced dipole

Question 37

The Coordination Number

Answer 37

Of an ion gives the number of its nearest neighbours

Question 38

Delocalised

Answer 38

Means that an electron is not attached to a particular atom

Question 39

Volatility

Answer 39

Describes how readily a substance vaporises

Question 40

Reversible Reaction

Answer 40

Is one that can go in either direction depending on the conditions

Question 41

Dynamic Equilibrium

Answer 41

Is when the forward and reverse reactions occur at the same rate

Question 42

Position of Equilibrium

Answer 42

Is the proportion of products to reactants in an equilibrium mixture

Question 43

Le Chatelier’s Principle

Answer 43

States that if a system at equilibrium is subjected to a change, the equilibrium tends to shift so as to minimise the effect of the change

Question 44

Acid

Answer 44

Is a proton donor

Question 45

Base

Answer 45

Is a proton acceptor

Question 46

Strong Acid

Answer 46

Is one that full dissociates in aqueous solution

Question 47

Weak Acid

Answer 47

Is one that partially dissociates in aqueous solution

Question 48

Salt

Answer 48

Is the compound that forms when a metal ion replaces the hydrogen ion in an acid

Question 49

Standard Solution

Answer 49

Is one for which the concentration is accurately known