Question

what element has 8 protons and a -2 charge?

Answer 1

Look at your periodic table and look at element number 8

Answer 2

Generally, when we talk about a certain element having a charge, this is representative of the amount of electrons it likes to take or give away in order to obtain the extremely stable noble gas configuration (the elements in Group 8 of the periodic table, the group on the extreme right-hand side).

So, if this certain element is present as an ion with a -2 charge, then atoms of this element like to exist with two extra electrons in order to complete a full outer shell of electrons (noble gas configuration). So, this means that it must already have 6 electrons present a a neutral atom.

We know that all elements in Group 6 (Oxygen, Sulfur, Selenium, etc...) have 6 electrons in their outer shell, so it must be one of these. In order to narrow it down, look at each of these element's atomic number written with it (number of protons/electrons it has) until you have found the correct answer. Hope that helps! :)