Atomic Theory Notes

Question 1

Alchemists

Answer 1

They were the people who proposed the first elements

In Europe

Question 2

The first elements

Answer 2

Fire
Water
Air/wind
Earth

Question 3

Purpose of Alchemists

Answer 3

To change metal(lead) into gold

Question 4

What are elements made of?

Answer 4

Atoms

Question 5

Aristotle

Answer 5

Came up with the concept of atoms in 2500BC

Question 6

John Dalton’s Atomic theory

Answer 6

1766
All matter is made up of small particles called atoms
Atoms cannot be created, destroyed, or divided into smaller particles
All atoms of the same element are identical in mass and size, but they are different in mass and size from other atoms of other elements
Compounds are created when atoms of different elements link together in definite proportions

Question 7

J.J Thomson

Answer 7

1856-1940
Discovered the electrons
Used the cathode ray tube to discover the electron
Proposed the plum pudding model

Question 8

Ernest Rutherford

Answer 8

1871-1937
Discovered the protons
Used the gold foil experiment to discover the proton
Proposed the nuclear model
Atoms mass is mostly nucleus
Atoms volume is mostly electrons

Question 9

Conclusion

Answer 9

The atom is mostly empty space with a solid, positive centre called a nucleus

Question 10

Niels Bohr

Answer 10

Proposed that electrons occupied energy levels called shells or orbitals

Question 11

Inside the atom

Answer 11

The atom is made up of subatomic particles

Question 12

3 subatomic particles

Answer 12

Protons, Neutrons, electrons

Question 13

Protons

Answer 13

Symbol: p
Relative mass: 1
Electric charge: positive
Location in atom: nucleus

Question 14

Newtrons

Answer 14

Symbol: n
Relative mass: Slightly more than 1
Electrical charge: 0, neutral
Location in atom: nucleus

Question 15

Electron

Answer 15

Symbol: e
Relative mass: almost 0, incredibly small
Electrical charge: negative
Location in atom: in the shells around nucleus