1.1 Fundamental particles

Question 1

What did Robert Boyle propose in 1661

Answer 1

. There were some substances that can’t be made similar
. These were chemical elements as we now know them

Question 2

What did John Dalton find about elements in 1803

Answer 2

. Suggested that elements are composed of invisible atoms
. All atoms of a particular element have the same mass,
And atoms of different elements have different masses.

Atoms can’t be broken down

Question 3

What did Henry Becquerel find in 1896

Answer 3

He discovered radioactivity, which showed that particles could come from inside the atom, therefore the atom is not indivisible.

Question 4

What did JJ Thompson find in 1897

Answer 4

He discovered the electron, which was the first sub atomic particle to be discovered. He showed that electrons were negatively charged and electrons from all elements were the same

This meant there must be positive charge as well , which accounted for more mass than electrons so he came up with the plum pudding model, electrons in a ball of positive charge

Question 5

What did Rutherford find in 1911

Answer 5

Most of the mass, and all of the positive charge of the nucleus is concentrated in the nucleus

Question 6

What sub atomic particles form the nucleus

What particles surround the nucleus on energy shells

Answer 6

Protons and neutrons

Electrons

Question 7

actual mass of protons, neutrons, and electrons

Relative mass

charge

Answer 7

p: Actual: 1.673 X 10^27
Relative: 1
Charge +1

N: Actual: 1.675 X 10^-27
Relative: 1
Charge: 0

E: Actual: 0.911 X 10^-30
Relative: 1/1840
Charge:-1

Question 8

How are protons and neutrons held together in the nucleus

Answer 8

Strong nuclear force holds them together.

This is much stronger than electrostatic forces of attraction that hold electrons and protons together in the atom, so it overcomes the repulsion between the protons in the nucleus