(N/A) $1$. $Carbocation$: $A$ species containing a carbon atom bearing a positive charge and having only $6$ electrons in its valence shell. It is an electron-deficient species (electrophile) with $sp^2$ hybridization and a planar geometry.
$2$. $Carbanion$: $A$ species containing a carbon atom bearing a negative charge and having $8$ electrons in its valence shell. It is an electron-rich species (nucleophile) with $sp^3$ hybridization and a pyramidal geometry.
$3$. $Free \text{ } radical$: $A$ species containing a carbon atom with an unpaired electron. It is formed by homolytic fission of a covalent bond. It is neutral,electron-deficient,and highly reactive.