# What must two atoms have the same if they represent the same element?

Nov 28, 2016

The identity of an element is detemined by $Z$, $\text{the atomic number}$, which gives the number of protons, massive nuclear particles of formal positive charge. And thus the Periodic Table of Elements reports elements on the basis of $Z$.
$Z = 1 , H$, $Z = 2 , H e$, $Z = 3 , L i$,....... $Z = 24 , C r$, ......$Z = 35 , B r$,