Atomic structure Flashcards
What and when was John Dalton’s contribution to developing the model of the atom?
Start of the 19th century - Atoms were first described as solid spheres.
What and when was JJ Thomson’s contribution to developing the model of the atom?
1897 - Plum pudding model.
What is the plum pudding model?
Ball of charge with electrons scattered within it.
What and when was Ernest Rutherford’s contribution to developing the model of the atom?
1909 - Alpha scattering expermiment.
What and when was Niels Bohr’s contribution to developing the model of the atom?
Around 1911 - Bohr theorised that the electrons were in shells orbiting the nucleus.
What and when was James Chadwick’s contribution to developing the model of the atom?
Around 1940 - Chadwick discovered neutrons in the nucleus.
What is an isotope?
An element with the same number of protons but a different number of neutrons.
What is beta radiation?
A fast moving electron that can be stopped by a piece of aluminium.
When is beta radiation emitted?
Beta radiation is emitted by an atom when a neutron splits into a proton and electron.
What is a gamma wave?
A wave of radiation and is the most penetrating - stopped by thick lead and concrete.
What is alpha radiation?
An alpha particle emitted
from the nucleus of a radioactive nuclei.
What is half life?
The time taken for the number of radioactive nuclei in an isotope to halve.
What is irradiation?
Irradiation occurs when materials are near a radioactive source. The source is sometimes placed inside a lead-lined box to avoid this.
