The History of the Atom

Question 1

Atoms

Answer 1

The tiny particles of matter which make up everything in the universe

Question 2

John Dalton

Answer 2

At the start of the 19th century he described atoms as solid spheres and said that different spheres make up different elements

Question 3

JJ Thompson

Answer 3

in 1897 he concluded from his experiments that atoms were not solid spheres. his measurements of charge and mass showed that an atom must contain even smaller negatively charges particles - electrons. The new theory was called the “plum pudding model”

Question 4

Ernest Rutherford

Answer 4

in 1909 he and his students conducted the gold foil experiment. they fired positively charged particles at an extremely thin sheet of gold. using his results he found the theory of the nuclear atom. positively charged nucleus at the centre surrounded by a cloud of negative electrons

Question 5

Niels Bohr

Answer 5

Proposed a new model of the atom where all electrons are contained by shells
Bohr suggested electrons can only exist in fixed orbits, or shells