What does a neutral atom always contain?

1 Answer
Nov 28, 2016

#"Protons"# and #"electrons"# in equal numbers.


The neutral atom may also contain #"neutrons"#, massive nuclear particles of zero charge. However, the protium isotope, #""^1H#, which is the most abundant material in the universe so far as I know, contains NO neutrons.

Protons, massive nuclear particles of unit positive charge, and electrons, extra-nuclear particles with negligible mass, AND unit negative charge, must be present in equal numbers in a neutral material, or atom.