In the following ions, what is the identity of element X? 

(a) X⁻  (anion, 18 electrons) 

(b) X⁺ (cation, 18 electrons)

If six electrons were removed from tungsten, ¹⁸⁴W, write the symbol of the ion formed.

Complete the following table by providing the missing information:

Which specific characteristic distinguishes ions from atoms?

Ions have a corresponding neutral atom with the same number of electrons. Identify the neutral atom that is isoelectronic with Al²⁺.