Unit 3 Practice Test -The Atom

Front

What must be true for an atom to be neutral?

Back

The atom has the same number of protons and electrons.

Front

What kind of ion is formed when a neutral atom loses electrons?

Back

Positive cation.

Front

What determines the identity of an element?

Back

Number of protons.

Front

How many electrons does an ion with a charge of +2 have if it originally had 12 electrons?

Back

10 electrons.

Front

An atom has an atomic number of 15 and a mass number of 31. How many neutrons does it have?

Back

16 neutrons.

Front

What is the charge of an atom with 10 protons and 8 electrons?

Back

Positive charge of +2.

Front

What is the mass number of an atom?

Back

The total number of protons and neutrons in the nucleus.

Front

What is an anion?

Back

A negatively charged ion formed when an atom gains electrons.

Front

What is a cation?

Back

A positively charged ion formed when an atom loses electrons.

Front

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

Back

Mass number - Atomic number.