An atom consists of a dense [[atomic nucleus]] of positively-charged [[proton]]s and electrically-neutral [[neutrons]], surrounded by a much larger [[electron cloud]] consisting of negatively-charged [[electron]]. An atom is electrically neutral if it has the same number of protons as electrons. The number of protons in an atom defines the [[chemical element]] to which it belongs, while the number of neutrons determines the [[isotope]] of the element. | An atom consists of a dense [[atomic nucleus]] of positively-charged [[proton]]s and electrically-neutral [[neutrons]], surrounded by a much larger [[electron cloud]] consisting of negatively-charged [[electron]]. An atom is electrically neutral if it has the same number of protons as electrons. The number of protons in an atom defines the [[chemical element]] to which it belongs, while the number of neutrons determines the [[isotope]] of the element. |