im not sure which one to answer, and i can hardly see the text.
Chromium has the electron configuration [Ar]4s13d5 and exhibits oxidation numbers 2+, 3+, and 6+. When chromium loses two electrons, it forms the Cr2+ ion and has the configuration [Ar]3d4.
The Answer is B. [Ar]3d4
101.325 kPa = 760 mmHg.
So, 25.0 kPa is 187.515 mmHg