The picture shows a close-up of one carbon atom. A hydrogen atom has one proton as the nucleus and one electron in the region outside the nucleus. The electron and proton are attracted to each other.

Symbol: A one or two-letter abbreviation used to represent the element. Atomic number: The number of protons in the nucleus ...

This symbol shows that chlorine has 35 particles ... as the number of electrons and protons are equal in a neutral atom, chlorine also has 17 electrons. The relative mass of a nucleus is the ...