Chapter 5.5, Problem 46PP

Use the periodic table to give the symbol of the element with each of the following electron configurations:
   $\begin{array}{l}\text{a}\text{.}{\text{1s}}^{\text{2}}{\text{2s}}^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^8\text{b}\text{.}[Kr]5s^{2}4d^{10}5p^4\\ \text{c}\text{.}1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^2\text{d}\text{.}{\text{[Ar]4s}}^{\text{2}}3d^{10}4p^5\end{array}$