History Of The Atomic Structure

Question 1

John Dalton

Answer 1

In 1803 Dalton devised the ‘billard ball’ in which he believed atoms where the smallest unit of atomic matter, so he envisioned the atom as a solid, hard sphere, like a billard ball.

Question 2

J.J Thompson ‘plum pudding model’

Answer 2

In 1897 J.J Thompson presented the idea that the atom wasn’t the smallest unit of matter but that atoms were made up of both positively and negatively charged subatomic particles. He believed electrons were surrounded by a volume of positive charge.

Question 3

Rutherford Model

Answer 3

From 1909-1911 Rutherford described the atom as a tiny, dense structure with a positively charged core, the nucleus; in which nearly all the mass was concentrated. Around the nucleus electrons circulated at a distance.

Question 4

Bohr model

Answer 4

In 1913 Bohr presented a model in which the electrons could only occupy certain orbits of the nucleus. Bohrs model was the first to use the quantum theory.

Question 5

Quantum mechanical

Answer 5

In 1913 this model was presented disregarding Bohrs model instead presenting that electrons move in waves in the space surrounding the atomic nucleus.

Question 6

Alpha scattering experiment

Answer 6

Rutherford fired alpha particles at a thin sheet of gold leaf and saw that some alpha particles didn’t go straight through but bounced back, this was the discovery of the nucleus.

Question 7

Why was lead used to surround the alpha Source?

Answer 7

So we can direct the alpha particles wherever

Question 8

What happens when an alpha particles hits the detector screen?

Answer 8

It flashes

Question 9

What was a microscope used for in the experiment?

Answer 9

To see the flashes