Early Ideas Of Atom Strucures

Question 1

Describe plum pudding

Answer 1

Atom is ball of positive charge with negative electrons embedded in it

Question 2

Findings of alpha scattering

Answer 2

• most alpha particles went straight through the gold atoms
  = atoms are mainly empty space
• some particles deflected
  = centre of atom must have positive charge
• some particles bounced straight back
  = centre of atom must have great deal of mass
  = called a nucleus

Question 3

Bohr findings

Answer 3

Idea of energy levels
= shells

Question 4

Chadwick findings

Answer 4

Nucleus contains neutral particles
= neutrons

Question 5

Relative charges of particles

Answer 5

Protons- 1
Neutrons- 0
Electrons- 1-

Question 6

Relative masses of particles

Answer 6

Proton- 1
Neutron- 1
Electron- very small

Question 7

Which is the atomic number

Answer 7

The bottom number
= protons and electrons

Question 8

How to workout neutrons

Answer 8

Mass number- atomic number

Question 9

Ideas of nuclear model (Bohr)

Answer 9

Mostly made of empty space
Positive charge all in nucleus
Mass in concentrated in nucleus
Electrons and nucleus are separate
Electrons are in orbits

Question 10

Ideas of plum pudding model

Answer 10

No empty space
Solid
Negative electrons embedded in atom

Question 11

Describe change Bohr made to nuclear model

Answer 11

Figured electrons orbit nucleus
Electrons are at specific distance from nucleus

Question 12

What is the atomic number

Answer 12

Protons

Question 13

Why Mendeleev reversed order of some pairs of elements

Answer 13

Properties match rest of group

Question 14

Disadvantages of particle model

Answer 14

Particles are shown as spheres
Doesn’t show movement or speed of particles
Doesn’t show element

Question 15

Limitations of dot and cross

Answer 15

Doesn’t show shape
Only 2 dimensional