Chapter 2 - Atoms: Structure and Mass

Question 1

Alpha Particle

Answer 1

A positively charged particle formed from ionising radiation.

Question 2

Atom

Answer 2

The basic building block of matter. It is made up of subatomic particles—protons, neutrons and electrons

Question 3

Atomic Number

Answer 3

The number of protons in the nucleus of an atom; identical to the charge number of the nucleus; symbol Z.

Question 4

Atomic Theory of Matter

Answer 4

All matter is made up of atoms. Atoms are indivisible, atoms of the same element are identical and compounds are made up of different types of atoms in fixed ratios.

Question 4

Chemical Symbol

Answer 4

A symbolic representation of an element, usually one or two letters, where the first letter is capitalised and the second letter
is lower case.

Question 4

Electron

Answer 4

A negatively charged, subatomic particle that occupies the region around the nucleus of an atom.

Question 5

Electrostatic Attraction

Answer 5

The force of attraction between a positively charged particle and a negatively charged particle.

Question 5

Mass Number

Answer 5

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

Question 6

Isotope

Answer 6

Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei.

Question 7

Mass Spectrometer

Answer 7

An instrument that measures the mass-to-charge ratio of particles.

Question 8

Matter

Answer 8

Anything that has a mass and occupies space

Question 8

Mass Spectrum

Answer 8

A plot of the isotopic mass, relative to the mass of carbon-12 taken as 12 units exactly, against the relative abundance of each isotope present in a sample.

Question 9

Model

Answer 9

A description that scientists use to represent the important features of a system or phenomenon

Question 10

Neutron

Answer 10

An uncharged subatomic particle found in the nucleus of an atom

Question 11

Nucleon

Answer 11

A particle that makes up the nucleus of an atom.

Question 12

Nucleus

Answer 12

The positively charged core at the centre of an atom, consisting of protons and neutrons.

Question 13

Periodic Table

Answer 13

A table that organises the elements by grouping them according to their electronic configurations.

Question 14

Proton

Answer 14

A positively charged, subatomic particle bound to neutrons in the nucleus of an atom.

Question 15

Radioactive

Answer 15

Spontaneously undergoing nuclear decay to produce radiation such as beta particles, alpha particles and gamma rays.

Question 16

Relative Atomic Mass

Answer 16

The weighted average of the relative isotopic masses of an element on the scale where 12C is taken as 12 units exactly

Question 17

Relative Isotopic Abundance

Answer 17

The percentage abundance of a particular isotope in a sample of an element

Question 18

Relative Isotopic Mass

Answer 18

The mass of an atom of the isotope relative to the mass of an atom of 12C taken as 12 units exactly

Question 19

Scanning Tunnelling Microscope (STM)

Answer 19

A microscope that images atoms by using a sharp metallic tip to sense the atoms on the surface of a crystal.

Question 20

Standard Atomic Weight

Answer 20

The relative atomic mass of an element based on the agreed proportions of isotopes in a ‘normal’ sample of the element on Earth.

Question 21

Subatomic Particle

Answer 21

A particle that makes up an atom - protons, neutrons and electrons