Atomic Number and Mass Number

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 do you calculate the mass number?

Back

Mass number = Number of protons + Number of neutrons.

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 does the atomic number relate to the number of electrons in a neutral atom?

Back

In a neutral atom, the number of electrons is equal to the atomic number.

Front

What is the relationship between protons and neutrons in an atom?

Back

Protons and neutrons together make up the mass number, but their individual counts can vary, leading to different isotopes.

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 protons does a Magnesium atom have?

Back

A Magnesium atom has 12 protons.

Front

If a phosphorus atom has 15 protons and 16 neutrons, what is its mass number?

Back

The mass number of the phosphorus atom is 31.

Front

What is the significance of the atomic mass?

Back

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

Front

What is the difference between atomic mass and mass number?

Back

Mass number is a whole number representing protons and neutrons, while atomic mass is a decimal that reflects the average mass of all isotopes.