Front

What is a proton?

Back

A proton is a positively charged particle found in the nucleus of an atom.

Front

What is a neutron?

Back

A neutron is a neutral particle (no charge) found in the nucleus of an atom.

Front

What is an electron?

Back

An electron is a negatively charged particle that orbits around the nucleus of an atom.

Front

What is the mass number of an atom?

Back

The mass number is the total number of protons and neutrons in the nucleus of an atom.

Front

How many protons are in a gold atom?

Back

A gold atom has 79 protons.

Front

How many neutrons are in a gold atom?

Back

A gold atom has 118 neutrons (197 mass number - 79 protons).

Front

What is the atomic number?

Back

The atomic number is the number of protons in the nucleus of an atom.

Front

What is the relationship between protons and electrons in a neutral atom?

Back

In a neutral atom, the number of protons equals the number of electrons.

Front

What is the atomic mass?

Back

The atomic mass is the weighted average mass of an atom's isotopes, measured in atomic mass units (amu).

Front

How do you find the number of neutrons in an atom?

Back

To find the number of neutrons, subtract the atomic number (protons) from the mass number.