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CfE Advanced Higher Chemistry Unit 1 > New words and meanings > Flashcards

Flashcards in New words and meanings Deck (31)
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1

Electromagnetic radiation

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

2

Electromagnetic spectrum

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

3

Wavelength

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

4

Frequency

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

5

Velocity

The speed at which a wave advances

6

Wavenumber

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

7

Photons

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

8

Quanta

The smallest “packet” of energy that can exist

9

Excited state

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

10

Ground  state 

The position of electrons in an atom under normal conditions

11

Atomic absorption/emission spectroscopy

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

 

12

Orbital

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

13

Heisenberg’s uncertainty principle

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.

14

Pauli exclusion principle

Electrons occupying the same orbital must have opposite spins.

15

Aufbau principle

Lower energy orbitals are filled before higher energy orbitals.

16

Degenerate

Of equal energy

17

Hund’s rule of maximum multiplictity

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

18

Spectroscopic/orbital box notation

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

19

Oxidation

An increase in oxidation number in a reaction

20

Reduction

A decrease in oxidation number in a reaction

21

Transition metal

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

22

Complex

A central metal ion surrounded by ligand.

23

Ligand

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

24

Monodentate ligand

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

25

Bidentate ligand

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

26

Polydentate ligand

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

27

Co-ordinate bond

A bond where the shared electrons are provided by one atom

28

Spectrochemical series

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

29

Entropy

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

30

Standard entropy

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