Nuclear Decay and Half Life

Front

What is the definition of half-life in nuclear decay?

Back

Half-life is the time required for half of the radioactive atoms in a sample to decay.

Front

If the half-life of a substance is 3 years, how much of a 100g sample remains after 9 years?

Back

12.5g remains after 9 years.

Front

What is the atomic number of Neptunium (Np)?

Back

93

Front

What is the atomic number of Actinium (Ac)?

Back

89

Front

Where does nuclear fusion occur naturally?

Back

Nuclear fusion occurs naturally in the sun.

Front

What is alpha decay?

Back

Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (2 protons and 2 neutrons) and transforms into a new element.

Front

Write the equation for the alpha decay of Astatine-209.

Back

₈₅²⁰⁹At = ₈₃²⁰⁵Bi + ₂⁴He.

Front

What is the significance of the atomic number in an element?

Back

The atomic number represents the number of protons in the nucleus of an atom and determines the element's identity.

Front

How do you calculate the remaining mass of a radioactive substance after multiple half-lives?

Back

Remaining mass = initial mass × (1/2)^(number of half-lives).

Front

What is the difference between nuclear fission and nuclear fusion?

Back

Nuclear fission is the splitting of a heavy nucleus into smaller nuclei, while nuclear fusion is the combining of light nuclei to form a heavier nucleus.