2.2 Atomic Number, Mass Number, and Isotopes

Front

What is the atomic number of an element?

Back

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

Front

How do you calculate the mass number of an atom?

Back

The mass number is calculated by adding the number of protons and neutrons in the nucleus.

Front

What is an isotope?

Back

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

Front

How many neutrons does Neon-22 have?

Back

Neon-22 has 12 neutrons.

Front

What is the atomic number of oxygen?

Back

The atomic number of oxygen is 8.

Front

How many protons are in a sodium atom (Na)?

Back

A sodium atom has 11 protons.

Front

What is the mass number of an atom with 6 protons and 6 neutrons?

Back

The mass number is 12 (6 protons + 6 neutrons).

Front

What is the relationship between atomic number and element identity?

Back

The atomic number uniquely identifies an element; no two elements have the same atomic number.

Front

Can an atom have the same mass number but different atomic numbers?

Back

No, atoms with different atomic numbers are different elements, even if they have the same mass number.

Front

What is the significance of the mass number in isotopes?

Back

The mass number helps distinguish between different isotopes of the same element.