Chapter Three, Lesson Five: Radioactive Elements

Question 1

radioactive decay

Answer 1

In a process called radioactive decay, the atomic nuclei of radioactive isotopes release fast-moving particles and energy.

Question 2

nuclear reactions

Answer 2

Nuclear reactions involve the particles in the nucleus of an atom.

Question 3

radioactivity

Answer 3

The ability to spontaneously emit radiation is called radioactivity.

Question 4

alpha particle

Answer 4

An alpha particle consists of two protons and two neutrons.

Question 5

beta particle

Answer 5

A beta particle is a fast-moving electron given off by a nucleus during radioactive decay.

Question 6

gamma rays

Answer 6

Gamma rays consist of high-energy waves, similar to X-rays.

Question 7

half-life

Answer 7

The half-life of a radioactive isotope is the length of time needed for half of the atoms of a sample to decay.

Question 8

radioactive dating

Answer 8

Scientists can calculate how many half-lives have passed since a plant died and estimate the age of the fossil. This process is called radioactive dating.

Question 9

tracers

Answer 9

Tracers are radioactive isotopes that can be followed through the steps of a chemical reaction or an industrial process.