Question

Use the periodic table to answer the question.

The periodic table of elements shows element groups, periods, and element properties.

Which element has atoms with valence electrons in a higher energy level than those of calcium (Ca)?

(1 point)
Responses

lithium (Li)
lithium (Li)

bromine (Br)
bromine (Br)

cesium (Cs)
cesium (Cs)

oxygen (O)

Answer 1

Calcium (Ca) has the electron configuration of [Ar] 4s², meaning its valence electrons are in the 4th energy level.

To determine which element has valence electrons in a higher energy level:

- **Lithium (Li)** has an electron configuration of 1s² 2s¹ (valence in the 2nd energy level).
- **Bromine (Br)** has an electron configuration of [Ar] 4s² 3d¹⁰ 4p⁵ (valence in the 4th energy level).
- **Cesium (Cs)** has an electron configuration of [Xe] 6s¹ (valence in the 6th energy level).
- **Oxygen (O)** has an electron configuration of 1s² 2s² 2p⁴ (valence in the 2nd energy level).

The only element listed that has valence electrons in a higher energy level than calcium (4th level) is **cesium (Cs)**, which has valence electrons in the 6th energy level.

So the correct answer is:

**cesium (Cs)**