Answer
a. $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10}5s^1$
b. $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10}4f^{14}5s^25p^65d^{10}6s^1$
c. $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10}4f^{14}5s^2 5p^6 5d^{10} 5f^3 6s^2 6p^6 6d^1 7s^2$
Work Step by Step
We write the configurations with the subshells in principal number order (e.g., 3d before 4s, as in Table 28–4).
a. Silver has Z = 47.
$$1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10}5s^1$$
b. Gold has Z = 79.
$$1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10}4f^{14}5s^25p^65d^{10}6s^1$$
c. Uranium has Z = 92.
$$1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10}4f^{14}5s^2 5p^6 5d^{10} 5f^3 6s^2 6p^6 6d^1 7s^2$$