atomic structure Flashcards
What did John Dalton’s ideas in 1804 consist of?
Matter was made up of tiny spheres (atoms) and each element was made up of a different type of ‘atom’.
What did JJ Thompson’s model of the atom consist of?
Plum Pudding Model: Discovered electrons and suggested atoms were spheres of positive charge with small negative electrons within it.
What did scientists realise from Rutherford’s Alpha Scattering Experiment in 1909?
That most of an atom’s mass was concentrated in a central nucleus.
What did Niels Bohr say an atom’s nucleus was made up of?
A group of protons with the same positive charge.
Who proved the existence of the electron in 1932?
James Chadwick.
What is the nucleus made up of in the current model of the atom?
Protons with a 1+ charge and neutral neutrons.
What is an isotope?
Atoms of the same element with the same number of protons but a different number of neutrons.
What is radioactive decay?
When unstable isotopes decay into other elements and give out radiation as they try to become stable.
What is ionising radiation?
Radiation that knocks electrons off atoms, creating positive ions.
What is an alpha particle made up of?
Two neutrons and two protons.
What is an alpha particle also known as?
A helium nucleus.
How far can alpha particles travel in air?
A few centimetres.
What are alpha particles absorbed by?
A sheet of paper.
How ionising are alpha particles?
Strongly ionising.
What are beta particles?
High speed electrons.
How ionising are beta particles?
Moderately ionising.
