## Q. 7.PS.7

Electron Configurations

Using only Figure 7.16 and the periodic table as a guide, give the complete electron configuration, orbital box diagram, and noble gas notation for vanadium, V.

## Verified Solution

$1s^22s^22p^63s^23p^63d^34s^2$

$[Ar] 3d^34s^2$

Strategy and Explanation The periodic table shows vanadium in the fourth period with atomic number 23. Therefore, vanadium has 23 electrons. Applying Figure 7.16, the first 18 are represented by $1s^22s^22p^63s^23p^6$, the electron configuration of argon, Ar, the noble gas that precedes vanadium. The last five electrons in vanadium have the configuration $3d^34s^2$. The orbital box diagram shown above follows from the total electron configuration.