Question

what is key to a atoms identity?

Answer 1

what do you think it is?

Answer 2

electrons

Answer 3

wait hold on, is that a quiz-

Answer 4

no

Answer 5

you kind of need to know/memorize this

we define atoms based on how many protons they have. for example, every atom with exactly 6 protons is carbon, regardless of how many electrons or neutrons it has. furthermore, if an atom has some different number of protons (like 5 or 7) then you know it' s not carbon.