# Why are atoms so different from one an another? [duplicate]

An atom is composed of a positively charge nucleus, with a cloud of electron(s) around it. But I can seem to understand the huge differences between 2 components that seem so close in terms of what they are made of.

I don't understand why adding one or 2 electrons, neutrons or protons, to get an other element, completely changes the behavior of said component.

## marked as duplicate by Bill N, Jon Custer, stafusa, John Rennie, YashasDec 13 '17 at 7:50

• @Goremant Neon has 8 outer electrons, saturating the $2s$ and $2p$ subshells against covalent bond formation, whereas fluorine has one fewer electron and can change that by forming a covalent bond that lets it share another electron originating from some other atom. – J.G. Dec 12 '17 at 22:04