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Flashcards in Atomic Theory Notes Deck (15)
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1

Alchemists

They were the people who proposed the first elements

In Europe

2

The first elements

Fire
Water
Air/wind
Earth

3

Purpose of Alchemists

To change metal(lead) into gold

4

What are elements made of?

Atoms

5

Aristotle

Came up with the concept of atoms in 2500BC

6

John Dalton's Atomic theory

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

7

J.J Thomson

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

8

Ernest Rutherford

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

9

Conclusion

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

10

Niels Bohr

Proposed that electrons occupied energy levels called shells or orbitals

11

Inside the atom

The atom is made up of subatomic particles

12

3 subatomic particles

Protons, Neutrons, electrons

13

Protons

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

14

Newtrons

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

15

Electron

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