Question

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

(1 point)
Responses

bromine (Br)
bromine (Br)

lithium (Li)
lithium (Li)

cesium (Cs)
cesium (Cs)

oxygen (O)

Answer 1

To find which element has atoms with valence electrons in a higher energy level than those of calcium (Ca), we first need to recognize the position of calcium in the periodic table. Calcium is in Group 2 (alkaline earth metals) and has the electron configuration of \([Ar] 4s^2\). This means its valence electrons are in the 4th energy level.

Now we can analyze the choices:

1. **Bromine (Br)**: Bromine is in Group 17 and has the electron configuration \([Ar] 4s^2 4p^5\). Its valence electrons are still in the 4th energy level.

2. **Lithium (Li)**: Lithium is in Group 1 with the electron configuration of \([He] 2s^1\). Its valence electrons are in the 2nd energy level, which is lower than that of calcium.

3. **Cesium (Cs)**: Cesium is in Group 1 and has the electron configuration \([Xe] 6s^1\). Its valence electron is in the 6th energy level, which is higher than the 4th.

4. **Oxygen (O)**: Oxygen is in Group 16 with the electron configuration \([He] 2s^2 2p^4\). Its valence electrons are in the 2nd energy level, which is lower than that of calcium.

Now we compare all of these:

- **Bromine (Br)**: 4th energy level
- **Lithium (Li)**: 2nd energy level
- **Cesium (Cs)**: 6th energy level (higher)
- **Oxygen (O)**: 2nd energy level

The only element from the options given that has valence electrons in a higher energy level than the valence electrons of calcium is **cesium (Cs)**.