Atomic Structure | Quizlet

Nucleus

centre of an atom; contains neutrons and protons

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

negatively charged particle; located outside the atomic nucleus, orbits the nucleus in energy shells

Atom

The basic unit of matter

Isotope

Atoms of the same element that have different numbers of neutrons

Ion

An atom or group of atoms that has a positive or negative charge.

Bohr Atomic Model

Atoms described as electrons orbiting the nucleus in well defined paths.

Proton (atomic) number

the number of protons in the nucleus of an atom

Mass (nucleon) number

The number of particles (protons and neutrons) in the nucleus.

Properties of electrons

- Negatively charged particles
- Relative mass = 1/1836
- Found in the energy shells
- (e-)

Properties of neutrons

- Particles with no charge
- Relative mass = 1
- Found in the nucleus of the atom
- (n0)

Properties of protons

- Particle with a positive charge
- Relative mass = 1
- Found in the nucleus of the atom
- (p+)

Ionisation

The removal of one or more electrons from an atom.

Radioactive decay

A spontaneous process in which unstable nuclei lose energy by emitting radiation

Alpha decay

A nuclear reaction in which an atom emits an alpha particle consisting of two protons and two neutrons. This increases the atomic number by 2 and the mass number by 4.

Beta decay

radioactive decay in which an electron is emitted.

Gamma decay

radioactive decay by emission of a gamma ray

Background radiation

nuclear radiation that occurs naturally in the environment

Geiger counter

instrument that measures radiation output

Electromagnetic radiation

a form of energy that exhibits wavelike behavior as it travels through space