Atomic Structure - The Atom

Question 1

What are the 5 atomic models?

Answer 1

• Dalton’s
• Thompson’s Plum Pudding
• Rutherford’s Model
• Bohr’s Planetary Model
• The Modern Model of the Atom

Question 2

What was Democritus’ Proposal?

3

Answer 2

• he proposed the idea of an atom
• it’s the smallest particle
• could not be split any further

Question 3

What was Dalton’s theory?

5

Answer 3

• atoms make up elements
• all atoms in one element are the same
• atoms of one element are different to the atoms of
  another element
• atoms are tiny
• atoms cannot be divided

Question 4

What was Thompson’s Plum Pudding?

1

Answer 4

• electrons move in a ‘sea’ of charge

Electrons = negative

Positively charged sphere

Question 5

What did Thomson experiment with and discover?

Answer 5

Cathode rays

Which allowed him to discover the electron

Question 6

What experiments did Rutherford do?

Answer 6

Fired alpha particles at a thin sheet of gold foil and measured the deflection of particles

Question 7

What particle deflections did Rutherford see?

3

Answer 7

Most particles didn’t deflect

A small proportion deflected through a large angle

Some deflected back towards the source

Question 8

What was Rutherford’s model?

4

Answer 8

• most of mass and charge of atom concentrated at the centre
• negative electrons orbit the central positive nucleus
• most of atoms volume came from space between tiny nucleus and electrons that orbit
• positive + negative charges balance to make atom neutral

Question 9

What was Bohr’s planetary model?

Answer 9

Electrons orbit the nucleus on paths

Question 10

What did Bohr’s model provide an explanation for?

Answer 10

The difference in energy of electrons at different distances from the nucleus

Question 11

After the planetary model, what did Rutherford discover?

Answer 11

The proton

Question 12

After the planetary model, what did Chadwick discover?

Answer 12

The neutron

Question 13

What is the modern day atom?

2

Answer 13

• atoms composed of sub-atomic particles (protons, neutrons, electrons)
• electrons surround the central nucleus

Question 14

Modern day atom

What are protons and neutrons made of?

Answer 14

Smaller quarks

Question 15

What is the timeline?

7

Answer 15

Daltons theory
Thomson’s plum pudding
Rutherford’s model
Bohr’s planetary model
Rutherford - discovered proton
Chadwick - discovered neutron
Modern day atom