Worksheet: Atomic Numbers and Mass Numbers

In this worksheet, we will practice defining and calculating the atomic numbers of elements and mass numbers of isotopes.

Q1:

Neon has an atomic number of 10. How many protons are there in an atom of neon?

Q2:

An aluminum atom has an atomic number of 13 and a mass number of 27.

How many protons are there in an atom of aluminum?

How many neutrons are there in an atom of aluminum?

How many electrons are there in an atom of aluminum?

Q3:

A fluorine atom has an atomic number of 9 and a mass number of 19.

How many protons are there in an atom of fluorine?

How many neutrons are there in an atom of fluorine?

How many electrons are there in an atom of fluorine?

Q4:

A carbon atom has an atomic number of 6 and a mass number of 12.

How many protons are there in an atom of carbon?

How many neutrons are there in an atom of carbon?

How many electrons are there in an atom of carbon?

Q5:

An atom of silicon has an atomic number of 14. How many electrons are there in an atom of silicon?

Q6:

An atom of sodium has a mass number of 23. What is the total number of protons and neutrons in the nucleus of the atom?

Q7:

An atom of calcium has a mass number of 42 and an atomic number of 20. How many neutrons are there in its nucleus?

Q8:

An atom of chlorine has a mass number of 35. What is the total number of protons and neutrons in its nucleus?

Q9:

An atom of sulfur has 16 protons in its nucleus. What is the atomic number of sulfur?

Q10:

An ion has atomic number 29, mass number 65 and a charge of 2+.

How many protons does the ion contain?

How many neutrons does the ion contain?

How many electrons does the ion contain?

What is the chemical symbol for this element?

  • A C o
  • B C u
  • C G a
  • D T b
  • E K r

Q11:

An ion has an atomic number of 50, a mass number of 116, and a charge of 4+.

How many protons does the ion contain?

How many neutrons does the ion contain?

How many electrons does the ion contain?

What is the chemical symbol for this element?

  • A D y
  • B P d
  • C X e
  • D S n
  • E L v

Q12:

An ion has an atomic number of 17, a mass number of 37, and a charge of 1.

How many protons does the ion contain?

How many neutrons does the ion contain?

How many electrons does the isotope contain?

What is the chemical symbol for this element?

  • A A r
  • B C l
  • C S
  • D R b
  • E C a

Q13:

Phosphorus-33 has an atomic number of 15. How many neutrons are there in an atom of phosphorus-33?

Q14:

The atomic number of helium-4 is half its mass number. How many neutrons are there in an atom of helium-4?

Q15:

Hydrogen has an atomic number of 1. How many neutrons are there in an atom of hydrogen?

Q16:

Phosphorus-31 has an atomic number of 15. How many neutrons are there in an atom of phosphorus-31?

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.