Answer: (e) the number of neutrons in the nucleus of an atom of the element
Explanation: The given information tells us how many electrons the atom has, and since the atom is neutral then the atomic number is the same as the total number of electrons. This rules out answer a. It also tells us that the element has a full set of valence electrons, making it a noble gas and ruling out answer b because noble gasses are known to act differently to other elements. c is ruled out because we are given the number of electrons, allowing us to figure out how many electrons are in s orbitals. The same goes for option d. This leaves option e. e is the correct answer because the number of neutrons in the nucleus of an atom does not affect the number of electrons or the charge of the atom, meaning we have no way of finding it.