Atomic Number and Mass Number

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

How is the atomic number related to the periodic table?

Back

The atomic number is used to arrange elements in the periodic table in increasing order.

Front

What is the mass number of an atom?

Back

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

Front

How do you calculate the mass number?

Back

Mass number = Number of protons + Number of neutrons.

Front

What is the atomic number of fluorine?

Back

The atomic number of fluorine is 9.

Front

If an atom has 10 neutrons and an atomic number of 9, what is its mass number?

Back

Mass number = 9 (protons) + 10 (neutrons) = 19.

Front

What does the atomic number tell you about an element?

Back

The atomic number indicates the number of protons and defines the element.

Front

What is the significance of protons in an atom?

Back

Protons determine the chemical properties and identity of an element.

Front

Can the atomic number change for an element?

Back

No, the atomic number is unique to each element and does not change.

Front

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

Back

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