Question

I am trying to complete one of those charts, where you find an element, its proton number, its electron number, it's charge, and whether it's an ion or an atom, based on looking at the Periodic Table. I get how it works, sort of, like for Lithium, you look at the number at the top (3), the horizontal number (2), and subtract three from two. But when I tried this same method with other elements, like Chlorine, it didn't work. For example, chlorine was number 17, in column seventeen, but my teacher says the number of electrons should be 18. Why is this? Thank you!

Answer 1

I am trying to complete one of those charts, where you find an element, its proton number, its electron number, it's charge, and whether it's an ion or an atom, based on looking at the Periodic Table. I get how it works, sort of, like for Lithium, you look at the number at the top (3), the horizontal number (2), and subtract three from two. But when I tried this same method with other elements, like Chlorine, it didn't work. For example, chlorine was number 17, in column seventeen, but my teacher says the number of electrons should be 18. Why is this? Thank you!