(a) Write the electron configuration for the element titanium, Ti. How many valence electrons does this atom possess?
(b) Hafnium, Hf, is also found in group 4B. Write the electron configuration for Hf.
(c) Ti and Hf behave as though they possess the same number of valence electrons. Which of the sub shells in the electron configuration of Hf behave as valence orbitals? Which behave as core orbitals?