6.4 Atomic Structure Flashcards
(24 cards)
Activity
The rate at which an unstable nucleus decays
Alpha Particle
A positively charged particle consisting of two protons and two neutrons
Atomic Number
The number of protons found in an atom of a specific element.
Each element has a different atomic number
Becquerel
The unit of radioactive activity
Beta Particle
A high speed electron that a nucleus emits when a neutron
converts into a proton
Bohr Model
A model of the atom that suggested that electrons orbit the nucleus at set distances
Count-Rate
The number of decays that a detector measures per second
Electrons
A negatively charged constituent of the atom, that are found in
different energy levels, around the nucleus
Energy Levels
The stable states in which electrons are found in around a
nucleus
Electrons can transition to a higher energy level through the absorption of electromagnetic radiation and can transition to a lower energy level through the emission of electromagnetic radiation
Gamma Ray
Electromagnetic radiation emitted from a nucleus
Geiger-Muller Tube
A detector that measures the count-rate of a radioactive sample
Half-Life
The time it takes for the number of unstable nuclei of an isotope in a sample to halve, or the time it takes for the initial count rate of a sample of the isotope to halve
Ions
Atoms with a resultant charge due to the loss or gain of electrons
Irradiation
The process of an object being exposed to nuclear radiation. The
object doesn’t become radioactive
Isotopes
Atoms with the same number of protons but different numbers of
neutrons.
The atomic number is the same, but the mass number is different
Mass Number
The number of protons and neutrons in an atom
Negative Ions
Atoms that gained electrons and so have a resultant negative charge
Neutrons
A neutrally charged constituent of the nucleus
Nucleus
The positively charged centre of an atom, containing protons and neutrons
Plum Pudding Model
An old model of the atom that represented the atom as a
ball of positive charge, with negative charges distributed throughout it.
Positive Ions
Atoms that have lost electrons and so have a resultant positive charge
Protons
A positively charged constituent of the nucleus
Radioactive Contamination
The unwanted presence of radioactive atoms on
other materials
It is hazardous due to the decay of the contaminating atoms
Radioactive Decay
The random process involving unstable nuclei emitting
radiation to become more stable
