What do all atoms in a piece of pure copper have in common?

1 Answer
Jun 10, 2017

All copper atoms have #"29 protons"# in their nuclei.

Explanation:

By definition, a copper atom has #"29 protons"#, 29 positively charged particles in their nuclei; i.e. #Z=29#. This is what defines the particle as a copper atom, i.e. #Z="atomic number"# determines the element.

The nucleus MAY contain approx. 34-35 neutrons, massive, neutrally charged particles, in their nuclei, and the differing number of neutrons gives rise to the existence of copper isotopes:

#""^63Cu, 69%;""^65Cu, 31%#.