1.1 — practice question

What is the electron arrangement for the particle $^{{27}}_{{13}}\mathrm{Al}^{+}$?

• A$1s^2 2s^2 2p^6 3s^1 3p^1$
• B$1s^2 2s^2 2p^6 3s^2$
• C$1s^2 2s^2 2p^6 3s^2 3p^2$
• D$1s^2 2s^2 2p^6 3s^2 3p^6 3d^7 4s^1$