An ionic compound made from the metal M and the diatomic gas X2 has the formula MaXb, in which a = 1 or 2 and b = 1 or 2. Use the data provided to determine the most likely values for a and b, along with the most likely charges for each of the ions in the ionic compound.
Data (in units of kJ/ mol)
Successive ionization energies of M: 480., 4750.
Successive electron affinity values for X: –175, 920.
Enthalpy of sublimation for M(s) → M(g): 110.
Bond energy of X2: 250.
Lattice energy for MX (M+ and X-): -1200. kJ/mol
Lattice energy for MX2 (M2+ and X-): -3500. kJ/mol
Lattice energy for M2X (M+ and X2-): -3600. kJ/mol
Lattice energy for MX (M2+ and X2-): -4800. kJ/mol