Proton number

The proton number of an atom is the number of protons it has in its nucleus.

We usually represent it with the letter Z, and sometimes call it the atomic number.

Proton number and elements

The proton number is important because it determines which element an atom is.

An element is defined by its proton number. For example:

You should be able to apply this pattern to all the elements on the periodic table!

flashcards

QuestionAnswer
Proton numberThe number of protons in an atom’s nucleus.
What letter represents proton number?Z
What is another name for proton number?Atomic number.
What determines which element an atom is?Its proton number (Z).
How is an element defined?By its proton number.
An atom with Z=1 is which element?Hydrogen.
An atom with Z=6 is which element?Carbon.
An atom with Z=8 is which element?Oxygen.