Return to MCAT® Blog Homepage

MCAT Chemistry Question — Electron Configuration

What is the electron configuration of calcium in CaCl2?

A) 1s22s22p63s23p5

B) 1s22s22p63s23p6

C) 1s22s22p63s23p64s1

D) 1s22s22p63s23p64s2

 

 

Explanation

 

This question asks the examinee to determine the electron configuration of the calcium ion, as it exists in calcium chloride. Calcium in its elemental state has a total of 20 electrons. Therefore Ca2+ has a total of 18 electrons. In the answer choices provided, choice B is the only electron configuration that contains 18 electrons making B the correct answer.

Want more MCAT practice?

We’ve got options for every schedule and learning style!

From the best online MCAT course created by top instructors with 524+ MCAT scores to the most representative full-length practice exams and private tutoring, we can custom tailor your MCAT prep to your goals!

Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT expert using the form below. No obligation, just expert advice.

Create your Free Account to access our MCAT Flashcards SIGN UP NOW
MCAT is a registered trademark of the Association of American Medical Colleges (AAMC), which is not affiliated with Blueprint.