Nuclear Chemistry

Question 1

three types of radiation

Answer 1

α (alpha)
β (beta)
γ (gamma)

Question 2

α (alpha) radiation

Answer 2

• Consists of positively charged particles that are attracted to the negative electrode in an electric field.
• These particles are helium nuclei (He 2+) and are written as as 4/2 α, meaning they contain two protons and two neutrons but lack electrons.

Question 3

β (Beta Radiation)

Answer 3

• Beta radiation consists of negatively charged electrons (β particles) that are attracted to the positive electrode in an electric field.
• A beta particle has a charge of -1 and does not contain protons or neutrons.
• It has a much smaller mass compared to a proton—1/1836th of a proton’s mass.
  It is represented as 0/-1 e

Question 4

γ (Gamma Radiation)

Answer 4

• Gamma radiation consists of high-energy photons with short wavelengths.
• Unlike alpha and beta radiation, gamma rays do not carry a charge and are not affected by electric or magnetic fields.
• The energy of gamma rays is determined by their frequency (𝜈) and follows the equation:
  𝜈 = Δ𝐸/ℎ
  where ΔE is the energy difference and h is Planck’s constant.

Question 5

DATA: Alpha radiation
Symbol:
Penetration:
Speed:
Particle:
Mass Number:
Charge:

Answer 5

Symbol: α
Penetration: Not very penetrating but can be damaging
Speed: 10% of the speed of light (c)
Particle: Helium-4 nucleus (4/2He 2+ , 4/2 α)
Mass Number: 4
Charge: +2

Question 6

DATA: Beta Radiation
Symbol:
Penetration:
Speed:
Particle:
Mass Number:
Charge:

Answer 6

Symbol: β
Penetration: Moderately penetrating
Speed: <90% of the speed of light (c)
Particle: Electron (0/-1 e, β- , e-)
Mass Number: 0
Charge: -1

Question 7

DATA: Electron Capture
Symbol:
Penetration:
Speed:
Particle:
Mass Number:
Charge:

Answer 7

Symbol: N/A
Penetration: N/A
Speed: N/A
Particle: Electron (0/-1e, e-)
Mass Number: 0
Charge: -1

Question 8

DATA: Gamma Radiation
Symbol:
Penetration:
Speed:
Particle:
Mass Number:
Charge:

Answer 8

Symbol: γ
Penetration: Very penetrating; often accompanies other radiation
Speed: Speed of light (c)
Particle: photon γ
Mass Number: 0
Charge: 0

Question 9

DATA: Positron Radiation
Symbol:
Penetration:
Speed:
Particle:
Mass Number:
Charge:

Answer 9

Symbol: β⁺
Penetration: moderately penetrating
Speed: <90% of the speed of light (c)
Particle: Positron (0/+1 e, β⁺)
Mass Number: 0
Charge: +1

Question 10

DATA: Proton Radiation
Symbol:
Penetration:
Speed:
Particle:
Mass Number:
Charge:

Answer 10

Symbol: p
Penetration: Moderate or low penetration
Speed: 10% of the speed of light (c)
Particle: Proton (1/1 H+, 1/1p, p)
Mass Number: 1
Charge: +1

Question 11

DATA: Neutron Radiation
Symbol:
Penetration:
Speed:
Particle:
Mass Number:
Charge:

Answer 11

Symbol: n
Penetration: Very penetrating
Speed: <10% of the speed of light (c)
Particle: Neutron (1/0n, n)
Mass Number: 1
Charge: 0`
]

Question 12

Nucleons

Answer 12

the protons and neutrons in the nucleus

Question 13

Nuclide

Answer 13

Atomic number + mass number + element symbol

Question 14

Stable vs radioisotopes

Answer 14

Stable isotopes: nuclei that don’t change over time

Radioisotopes: nuclei that spontaneously emit radiation

Question 15

α-decay

Answer 15

A -> B + 4/2α

Question 16

Transmutation

Answer 16

where one element transforms into another due to nuclear decay

Question 17

β-decay

Answer 17

n → p + β

Question 18

Electron Capture

Answer 18

When a nucleus captures an inner-shell electron and combines it with a proton to form a neutron.

1/1p + −1/0e → 0/1n

Question 19

Positron Emission

Answer 19

When a proton is converted into a neutron and emits a positron (𝛽+).

Question 20

Pattern of Nuclear Stability

Answer 20

• Some atomic nuclei are more stable than others.
• Even numbers of protons and neutrons tend to create more stable isotopes compared to odd numbers.

Question 21

Magic Numbers

Answer 21

• Certain atomic numbers have the highest number of stable isotopes and are called magic numbers:
  2, 8, 20, 50, 82, 114, 126, and 184.
• These numbers correspond to completely filled nuclear shells, which enhance nuclear stability.

Question 22

Neutron-to-Proton Ratio of Stability Trends

Answer 22

z<_20, 1:1 ratio is stable
z> 20, 2:1 ratio is stable

This is because strong nuclear forces between neutrons help counteract the electrostatic repulsion between protons.

Question 23

Kinetics of Nuclear Decay

Answer 23

short half-life = high activity