Question

What is the decimal at the bottom of an element on the periodic table​?

Answer 1

Atomic mass

Explanation:

That number is the atomic mass of the element. It is also the same numerical value as the molar mass, which is the mass of 1 mole of the element.

So, in this case, sodium (Na) has an atomic mass of 22.99 atomic mass units (amu).

Hope this helps!

Answer 2

The atomic mass

Explanation:

The decimal at the bottom of an element represents how much one atom of that element weighs.