Question

Consider a hypothetical atom with an atomic number of 4 and a net electronic charge of + 1. It has 4 protons. How many neutrons does this atom have?

Answer 1

We know that the atom is `"beryllium"` if `Z=4` (why?). The number of neutrons is likely `5`.

Explanation:

`Z", the atomic number"`, is the number of protons, massive positively charged particles present in the nucleus. `Z` defines the element, and if `Z=4`, the element beryllium is specified.

While beryllium has several isotopes, `""^9Be` is the most common, and certainly overwhelmingly abundant. Even at A level, however, (or even at 1st year undergraduate level), it would not be appropriate to ask a student which is the most stable beryllium nuclide.