IMPORTANT Evolution of Atomic Theory

Question 1

Name of Scientists in order of time

Answer 1

• John Dalton
• J.J. Thompson
• E. Rutherford
• Niels Bohr

Question 2

Experiment used by John Dalton

Answer 2

Used different gases and liquids to study chemical changes

Question 3

Experiment used by J.J. Thomson

Answer 3

Used gas discharge tubes to study the effects of applying electric currents to gasses at low pressure

Question 4

Experiment used by E. Rutherford

Answer 4

• “Gold Foil Experiment”
• Aimed positively charged particles at a thin sheet of gold foil
• Looked at where the particles ended up on a screen

Question 5

Experiment used by Niels Bohr

Answer 5

Studied the coloured banding pattern of elements that result from electric currents

Question 6

Major Finding of John Dalton …

Answer 6

First person to discover the concept of the atom

• All matter is made of atoms
• Atoms cannot be CDD (created, divided, destroyed)
• All atoms of the same matter are identical in mass and size
• Compounds are created when atoms of different elements combine

Question 7

Major Finding of J.J. Thomson …

Answer 7

• Atoms had negative particles
• Rays travel from cathode (-) to anode (+)
• Same negative charge found in all gasses

Question 8

Major Finding of … E. Rutherford

Answer 8

Most particles passed through foil

• Some particles were deflected
• Discovered that atoms have a positive nucleus
• Proposed that negative particles must revolve around it
• Most of the atom is empty space

Question 9

Major Finding of … Niels Bohr

Answer 9

Found electrons can only move in fixed regions

• Electrons move to different rings by adding or removing specific amounts of energy
• (This is why electrons don’t crash into the nucleus)

Question 10

What are IONIC COMPOUNDS composed of?

Answer 10

ONE metal and ONE non-metal

Question 11

What are COVALENT COMPOUNDS composed of?

Answer 11

only NON-METALS