Why does boron not form {B^{3 + }} ion?

Boron does not typically form a B^3+ ion because it does not have enough electrons in its atomic structure to lose three electrons and attain a stable electron configuration.

Boron, with an atomic number of 5, has the electron configuration of 1s² 2s² 2p¹. In its neutral state, it has three electrons. In order to form a B^3+ ion, it would need to lose all three of these electrons, which would result in an electron configuration of 1s². Having only two electrons in its electron configuration would make it highly unstable because it would not have a filled outermost energy level or satisfy the octet rule (having eight electrons in the outermost energy level).

To achieve a more stable electron configuration, boron tends to form compounds by sharing electrons (covalent bonding) or accepting electrons from other elements (ionic bonding) rather than losing all three of its electrons to become a B^3+ ion. In most compounds, boron forms covalent bonds, sharing its single electron with other atoms to complete its valence shell and achieve a more stable configuration.