Atomic Structure

Question 0

What is the charge of a proton?

Answer 0

+1.60 x 10^-19 coulombs

Question 1

What are nucleons?

Answer 1

Protons and neutrons.

Question 2

What is the mass of a proton?

Answer 2

1.67 x 10^-27 kilograms

Question 3

What is the charge of a neutron?

Answer 3

0

Question 4

What is the mass of a neutron?

Answer 4

1.67 x 10^-27 kilograms

Question 5

What is the charge of an electron?

Answer 5

-1.60 x 10^-19 coulombs

Question 6

What is the mass of an electron?

Answer 6

9.11 x 10^-31

Question 7

What is the proton number?

Answer 7

Number of protons in an atom.

Question 8

What is the symbol of the proton number?

Answer 8

Z

Question 9

What is the nucleon number?

Answer 9

The number of protons and neutrons in an atom.

Question 10

What is the symbol for the nucleon number?

Answer 10

A

Question 11

What is the specific charge of a particle?

Answer 11

The ratio of a particles charge to it’s mass.

Question 12

What is the equation for calculating specific charge?

Answer 12

Specific charge = charge/mass

Question 13

What is the unit for specific charge?

Answer 13

Coulombs/kg (CKg^-1)

Question 14

What is an isotope?

Answer 14

An atom with the same number of protons but different numbers of neutrons.

Question 15

Name the three main forces acting on the nucleus.

Answer 15

• electromagnetic force
• gravitational force
• strong nuclear force

Question 16

What role does the electromagnetic force play inside the atom?

Answer 16

Causes positively charged protons in the nucleus to repel each other.

Question 17

What role does gravitational force play inside the atom?

Answer 17

Causes all the nucleons in the nucleus to attract each other due to their mass.

Question 18

What role does the strong nuclear force play inside the nucleus?

Answer 18

The repulsive electromagnetic force is much larger than the attractive gravitational force. This means there is another force holding the nucleus together. This is the SNF.

Question 19

What is the range of the strong nuclear force?

Answer 19

A few femtometres ( 1 fm = 1 x 10^-15) - the size of a nucleus.

Question 20

What prevents the strong nuclear force from crushing the nucleus?

Answer 20

The SNF must be repulsive at very small separations.

Question 21

What conclusion can be drawn from the fact that the size of the SNF is the same whether between proton-proton, neutron-proton, neutron-neutron?

Answer 21

The strong nuclear force works equally between all nucleons.

Question 22

What is nuclear decay?

Answer 22

The emission of unstable particles from the nuclei.

Question 23

When does alpha decay occur?

Answer 23

Alpha decay occurs in atoms that contain 82 or more protons.

Question 24

Why does alpha decay occur?

Answer 24

The nuclei is too big for the strong nuclear force to keep them stable.

Question 25

State the nucleon and proton number of an alpha particle.

Answer 25

Nucleon number - 4

Proton number - 2

Question 26

By what amount does the nucleon and proton number of the atom, that the alpha particle is emitted from, decrease by?

Answer 26

Nucleon number decrease by 4.

Proton number decreases by 2.

Question 27

What is beta-minus decay?

Answer 27

The emission of an electron from the nucleus along with an anti neutrino particle.

Question 28

When does beta-minus decay?

Answer 28

Beta-minus decay happens in isotopes that are “neutron rich” - an isotope that has too many neutrons compared to protons.

Question 29

What happens when a beta particle is emitted from an isotope?

Answer 29

• a neutron in the nucleus changes to a proton.
• the proton number increases by one.
• nucleon number stays the same.

Question 30

What is the purpose of the anti-neutrino particle in beta-minus decay?

Answer 30

The antineutrino particle carries away some energy and momentum.