Unit 1&2-Glossary

Question 1

Electromagnetic radiation

Answer 1

can be described in terms of waves and characterised in terms of wavelength and/or frequency.

Question 2

Electromagnetic spectrum

Answer 2

Radiowave-microwaves-infrared-visible-ultraviolet-xrays-gamma rays

Question 3

Wavelength

Answer 3

The length of a complete wave (e.g. measured from one crest to another).

Question 4

Frequency

Answer 4

The number of waves passing a fixed point per second. Given the unit of Hertz (Hz)

Question 5

Velocity

Answer 5

The speed at which a wave advances

Question 6

Wavenumber

Answer 6

The number of waves in a given distance (e.g. per metre or per centimetre)

Question 7

Photons

Answer 7

A particle or packet on energy carried as part of the electromagnetic spectrum (often as visible light).

Question 8

Quanta

Answer 8

The smallest “packet” of energy that can exist

Question 9

Excited state

Answer 9

The position of electrons in an atom after it has absorbed a photon of energy, promoting electrons to higher energy levels.

Question 10

Ground state

Answer 10

The position of electrons in an atom under normal conditions

Question 11

Atomic absorption/emission spectroscopy

Answer 11

An analytical technique which measures the intensity of light being absorbed/emitted by a sample. This is proportional to the concentration of the sample.

Question 12

Orbital

Answer 12

A region of space which can hold a maximum of two electrons.

Question 13

Heisenberg’s uncertainty principle

Answer 13

It is impossible to know the exact position and velocity of an electron at any given time. We can only define areas of probability of finding an electron called an orbital.

Question 14

Pauli exclusion principle

Answer 14

Electrons occupying the same orbital must have opposite spins.

Question 15

Aufbau principle

Answer 15

Lower energy orbitals are filled before higher energy orbitals.

Question 16

Degenerate

Answer 16

Of equal energy

Question 17

Hund’s rule of maximum multiplictity

Answer 17

Electrons occupy all degenerate orbitals singly, with their spins in the same direction, before pairing up (and reversing their spin).

Question 18

Spectroscopic/orbital box notation

Answer 18

A method of fully describing the arrangement of electrons in an atom.

Question 19

Oxidation

Answer 19

An increase in oxidation number in a reaction

Question 20

Reduction

Answer 20

A decrease in oxidation number in a reaction

Question 21

Transition metal

Answer 21

a metal which has an incomplete d subshell in one of it ions.

Question 22

Complex

Answer 22

A central metal ion surrounded by ligand.

Question 23

Ligand

Answer 23

electron donors which may be negative ions or molecules with non-bonding pairs of electrons

Question 24

Monodentate ligand

Answer 24

negative ions or molecules which donate one non-bonding pair of electrons to a central metal ion

Question 25

Bidentate ligand

Answer 25

Negative ions or molecules which donate two non-bonding pairs of electrons to a central metal ion

Question 26

Polydentate ligand

Answer 26

negative ions or molecules which donate more that one non-bonding pair of electrons to a central metal ion.

Question 27

Co-ordinate bond

Answer 27

A bond where the shared electrons are provided by one atom

Question 28

Spectrochemical series

Answer 28

A list of ligands arranged in order of the extent of d-splitting (Δ) that the ligand causes

Question 29

Entropy

Answer 29

a measure of the degree of disorder (or chaos) in a system.

Question 30

Standard entropy

Answer 30

a measure of the degree of disorder (or chaos) in a system.

Question 31

Free energy

Answer 31

the part of the total energy of a system that can do work at constant temperature and pressure completely.