Question

If we have an atom for which `Z=17` that possesses `"16 electrons"`, how would we represent it symbolically?

Answer 1

If `Z`, the atomic number, `=` `17`, the element MUST be chlorine.

Explanation:

The atomic number relates to the number of protons, fundamental positively charged particles in the nucleus. The number of protons defines the element. Because there are `16` electrons only (negatively charged particles which orbit the nucleus), we would represent the element as `Cl^+`, which is an unusual situation for this element to be in (normally it forms the `Cl^-` ion!). There are 6 valence electrons on this species.

Do you have to remember this? No, because you should always be given a copy of the Periodic Table. You should have access to one now, and you certainly should be able to tell me what element we have when `Z` `=` `16`, and `Z` `=` `18`.