What two particles account for almost all of the mass of an atom?

1 Answer
Jul 5, 2018

#"Protons and neutrons..."#

Explanation:

The atom is composed of massive particles of formal positive, and neutral electronic charge, around which electrons, negatively-charged particles of negligible mass, whizz about. At nuclear ranges, which are MINUTE, the massive particles engage in the #"strong nuclear force"#, an attractive force which holds the nucleus together. The electronic charge signs of the electrons and the charged-nuclear particles are entirely arbitrary....the point is that that they oppositely charged...

Note that sometimes we refer to a #""^1H^+# particle as a #"proton"#. This is a bit of a misnomer even tho' it is technically true… because such protons are present in the nuclei of ALL elements. The number of protons determines #Z_"the atomic number.."#. How does the number of electrons relate to #Z#?