Nuclear/ Particle

Question 1

Thompson plum pudding model

Answer 1

neutral atom made up of a uniform sphere of positive charge with tiny electrons embedded

Question 2

Observations form Rutherford’s gold foil experiment

Answer 2

• most alpha particles travel through foil un deflected
• some alpha particles deflected by small angles
• occasionally an alpha particle travels back from the foil

Question 3

Interpretation of Rutherford’s foils foil experiment

Answer 3

• atom mostly empty space
• nucleus is positively charged, as is the alpha particle
• nucleus carries most of atom’s mass

Question 4

What did Rutherford conclude about the atom

Answer 4

The atom has a small dense nucleus which contains most of the mass of the atom and is positively charged

Question 5

What suggestions did Rutherford further make about the atom

Answer 5

The nucleus was surrounded by orbiting negative electrons - shown by planetary model

Question 6

What are isotopes

Answer 6

Atoms of the same element with differing numbers of neutrons

Question 7

If it is the same element but with differing amounts of neutrons what does this mean

Answer 7

Can undergo same chemical reactions but will undergo different nuclear reactions due to their electronic configurations being identical but stability of their nuclei may differ greatly

Question 8

What is a nucleon

Answer 8

A subatomic particle that resides in the nucleus (either a proton or neutron)

Question 9

How can the subatomic particle constituents of an atom be represented

Answer 9

• atomic or proton number Z
• mass number A

Question 10

What is the mass number

Answer 10

Also known as the nucleon number, is a sum of the number of protons and neutrons in the nucleus

Question 11

How can you estimate the mass of an atom

Answer 11

By multiplying mass number by atomic mass unit

1U = 1.661 x 10^-27 kg

Question 12

What are the four fundamental forces in the universe

Answer 12

• gravitational force
• electromagnetic force
• weak nuclear force
• strong nuclear force

Question 13

Explain gravitational force

Answer 13

• acts on particles with mass
• always attractive
• infinite range but very weak

Question 14

Explain electromagnetic force

Answer 14

• infinite range
• acts on particles with charge

Question 15

Explain weak nuclear force

Answer 15

• force responsible for beta decay
• acts to change quark types over very small distances

Question 16

Explain strong nuclear force

Answer 16

• acts between all nucleons and quarks
• counteracts repulsive electrostatic forces between protons in the nucleus
• attractive at small distances
• repulsive at incredibly small distances
• limited range