Question

which element has atoms with valence electrons in a higher energy level than those of calcium (ca)? (1 point) o strontium (sr) o carbon (c) o oxygen (o) o neon (ne)

Explanation:

Step1: Identify calcium's electron - shell information

Calcium (Ca) is in the 4th period of the periodic table. Its valence electrons are in the 4s orbital.

Step2: Analyze each option

• Strontium (Sr) is in the 5th period. Its valence electrons are in the 5s orbital, which is a higher energy level than the 4s orbital of calcium.
• Carbon (C) is in the 2nd period. Its valence electrons are in the 2s and 2p orbitals, which are lower energy levels than calcium's valence - electron orbital.
• Oxygen (O) is in the 2nd period. Its valence electrons are in the 2s and 2p orbitals, lower energy levels than calcium's.
• Neon (Ne) is in the 2nd period. Its valence electrons are in the 2s and 2p orbitals, lower energy levels than calcium's.

Answer:

A. Strontium (Sr)