c1 particles

Question 1

Atom

Answer 1

smallest particle of an element. Atoms have a nucleus containing protons and (usually) neutrons, surrounded by electrons.

Question 2

Atomic number

Answer 2

number of protons in the nucleus of an atom.

Question 3

Atomic radius

Answer 3

half the diameter of an atom.

Question 4

Bond

Answer 4

attractive force between two particles.

Question 5

Bond length

Answer 5

distance between the centres of two atoms that are chemically joined together.

Question 6

Chemical symbol

Answer 6

letter or letters used by chemists to represent an element, e.g. the symbol for mercury is Hg.

Question 7

Electron

Answer 7

subatomic particle surrounding the nucleus of an atom. It has a relative charge of -1, and a very small mass.

Question 8

Element

Answer 8

substance whose atoms have the same atomic number.

Question 9

Ion

Answer 9

charged particle formed when an atom, or group of atoms, loses or gains electrons.

Question 10

Isotopes

Answer 10

atoms with the same number of protons and electrons, but different numbers of neutrons, are isotopes of the same element.

Question 11

Mass number

Answer 11

number of protons and neutrons in a nucleus.

Question 12

Molecule

Answer 12

particle consisting of two or more non-metal atoms chemically joined together by covalent bonds.

Question 13

Neutron

Answer 13

subatomic particle found in the nucleus of an atom. It has no charge and a relative mass of 1.

Question 14

Nucleus

Answer 14

positively charged central part of an atom, made up of protons and neutrons.

Question 15

Plum-pudding model

Answer 15

outdated model of the atom in which electrons are embedded in a sphere of positive charge.

Question 16

Protons

Answer 16

subatomic particle found in the nucleus of an atom. It has a relative charge of +1 and a relative mass of 1.

Question 17

Shell

Answer 17

region of space in an atom that can hold a certain number of electrons.

Question 18

Subatomic particle

Answer 18

articles from which atoms are made, including protons, neutrons, and electrons.

Question 19

Chemical change

Answer 19

change that produces new substances.

Question 20

Chemical reaction

Answer 20

process in which substances react to form different substances.

Question 21

Electrostatic forces

Answer 21

forces of attraction or repulsion between electrically charged particles.

Question 22

Matter

Answer 22

anything that has mass.

Question 23

Model

Answer 23

description, analogy, or equation that helps you to explain the physical world.

Question 24

Particle

Answer 24

tiny piece of matter, such as an atom, ion, or molecule.

Question 25

Particle model

Answer 25

scientific idea used to explain the properties of solids, liquids, and gases.

Question 26

Physical change

Answer 26

change, such as changes in state that does not result in new substances being made.

Question 27

State

Answer 27

the form that a substance has (solid, liquid, or gas) under given conditions of temperature and pressure.