Give the symbols for 4 species that are isoelectronic with the telluride ion, te2-.

Answer: Chlorine has 17 electrons therefore for 1 + and 2 + we need the atoms that have 18 and 19 electrons these are argon and potassium: Ar + and K 2 + For 1 - and 2 - we need the atoms that have 16 and 15 electrons and these are sulfur and phosphorus, S - and P 2-. Note that + ions imply the loss of electrons and - ions equate to the gain of electrons.