Atomic Number, Mass Number and Isotopes

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 is an element identified?

Back

An element is identified by its atomic number, which is the number of protons in its nucleus.

Front

What is the atomic number of an element?

Back

The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity.

Front

What are isotopes?

Back

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.

Front

If an atom has 12 neutrons and 11 protons, what is its mass number?

Back

23 (Mass number = protons + neutrons = 11 + 12).

Front

What is the mass number of Li-7?

Back

The mass number of Li-7 is 7, which means it has 3 protons and 4 neutrons.

Front

True or False: The atomic number is the same as the mass number.

Back

False. The atomic number is the number of protons, while the mass number is the total of protons and neutrons.

Front

How many neutrons does Li-6 have?

Back

Li-6 has 3 neutrons (Mass number 6 - Atomic number 3 = 3 neutrons).

Front

What is the relationship between protons and neutrons in isotopes?

Back

Isotopes have the same number of protons but different numbers of neutrons.

Front

If an atom has 7 protons, what is its atomic number?

Back

The atomic number is 7, which identifies the element as nitrogen.