L1- Introductory Atom Models.

Question 1

What was Thomson’s model?

Answer 1

Thomson’s model was the plum-pudding model of the atom, in which the atom is thought to consist of positive mass with negative electrons embedded in it. He did not know what the positive mass was made of or the structure. He thought the positive mass might be solid, or like a cloud.

Question 2

What was Dalton’s model?

Answer 2

His model was of a small, indestructible sphere. He thought that all atoms were the same, and that the atoms in one element were different to all the ones in other elements.

Question 3

What was Democritus and Leucippus’ model?

Answer 3

They believed atoms were small, indestructible spheres.

Question 4

When and how did Dalton discover his model?

Answer 4

In the 1870s, John Dalton did experiments to measure how elements combined. He thought that he could explain the results if everything is made of atoms.

Question 5

When and how did Thomson discover his model?

Answer 5

In 1897, J.J. Thomson was investigating rays given out by hot metals called cathode rays, when he discovered cathode rays are made of particles (electrons) that have less than one-thousandth the mass of a hydrogen atom.

Question 6

What did “atomos” mean and in what language?

Answer 6

Atomos means “indivisible” in Greek.