20
RCMultiple Choice

Cumulative Exam — Cumulative exam

Question 20 • MI-Chemistry A-CR

What is the electron configuration for helium (He)?

Answer
A
1s1
B
1s2
C
1s22s1
D
1s22s2

Explanation

Helium has atomic number 2, so a neutral helium atom has two electrons. The 1s orbital fills first and can hold up to two electrons, giving the configuration 1s². Therefore, choice B, 1s2, is correct.

AI-written and checked against the verified answer.

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