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:
-
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.
-
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.
-
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.
-
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).
1 answer