Question
Question: Common oxidation state of scandium, a transition element is / are a. \[ + 3\] b. \( + 1\) c. ...
Common oxidation state of scandium, a transition element is / are
a. +3
b. +1
c. +2 and +3
d.+4 and +1
Solution
Scandium has atomic number 21. According to its electronic configuration, we have to determine which oxidation state will be stable for scandium. It is a silvery white metallic element. It changes its color to slightly pink or yellow when exposed to air.
Complete answer:
Scandium has atomic number 21. Valence shell configuration is 3d14s2. When we calculate the energy for vacant orbitals, we see that 4s orbital has less energy. That’s why 4s orbital gets filled at first. Then 3d orbital gets filled. But in case of fulfilled orbitals, 4s orbital has greater energy than 3d orbital. That’s why electrons are removed from the 4s orbital first. By calculating z effectively, we can easily determine that. If only one electron is removed making the +1oxidation state, it will not be stable as there will be 3d14s1 configuration. If two electrons are removed, only one electron will be remaining in 3d orbital. That is not stable. If three electrons are removed, there will be zero electrons in 3d and 4s orbitals. There will be fulfilled orbitals upto 3p orbital. This will be stable. If four electrons are removed, that will not be stable because there will be four electrons in 3p orbital. Fulfilled and half-filled configurations are only stable. From this, we can easily tell that +3 oxidation state is only stable for scandium. In other states, Scandium does not have full filled or half-filled configurations.
Hence, option (A) is the correct answer.
** Note:**
Thus, it can be concluded that +3 oxidation state is stable for scandium. The fact that full filled and half-filled valence shell configurations are stable, is applicable for all the elements. Scandium is used to make high intensity lighting and also mercury vapor lamps. The light produced by scandium is similar to sunlight.