Nuclear Decay and Half Life

What is Half-life?

• The amount of time it takes for some of the nuclei in a sample of the isotope to decay
• The amount of time it takes for half the electrons in a sample of the isotope to decay
• The amount of time it takes for half the nuclei in a sample of the isotope to decay
• the amount of time it takes to double the nuclei in a sample of the isotope to decay

The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 7.2 minutes has elapsed?

• 100.0g
• 50.0g
• 12.5g
• 8.5g

After the third half-life, how much of the sample is left?

• 1/2
• 1/3
• 1/16
• 1/8

Describe the structure of an alpha particle.

• a fast-moving electron

• 2 protons and 2 neutrons

• a slow-moving neutron

• a hydrogen nucleus

The mass number of Neptunium (Np) is _____.

The atomic number of Neptunium (Np) is _____.

The atomic number of Actinium (Ac) is _____.

Solve this equation for alpha decay.
₈₅²⁰⁹At = ___ + ₂⁴He

• ₈₃²⁰⁵Bi
• ₈₆²⁰⁹Rn
• ₈₁²⁰⁷Tl
• ₈₅²⁰⁸At

Solve this equation for beta decay.
₆¹⁴C = ___ + _-1⁰e

• ₄¹⁰Be
• ₇¹⁴N
• ₂¹⁰He
• ₆¹³C

During beta-particle emission, a neutron splits into a____________________.

• proton and electron

• neutron and electron

• neutron and proton