3. Answer the following questions and explain the reason. a) Which of the following elements has the lowest first ionization energy? Be, Mg, Ca, S, Si b) Order the ions Na+, Mg2+, and Al3+ in terms of increasing ionic radius.

   c) Which molecule/ion below has the largest dipole? And why? CO2, SiH4, SO2, BF4-, F2 d) Describe quantum number sets for 4 f orbital.