system
Given the following post, respond as if you're commenting on Reddit:
human
If the only thing that differentiates elements from one another is the number of protons in the nucleus, why isn't there a steady gradient of characteristics on the periodic table?

I know I'm oversimplifying the differences between elements, but if I understand high school physics correctly an atom of carbon, for example, could have isotopes with fewer or more neutrons, and I know that atoms trade and lose and gain electrons all the time. It follows that the only defining factor is the number of protons, correct?

If so then why does carbon's 6 protons give it the characteristics it has, yet nitrogen's 7 protons give it such drastically different characteristics? Is there something big I'm missing about why elements are the way they are?
gpt
The way things interact with each other is mostly by electrons and electrons come in shells where at certain numbers you get a new outside shell and the new inside ones don't matter as much. elements in a vertical row on the periodic table have the same number of electrons on the outside shell and they tend to be more similar.