Secondary carbocation

Primary carbocation

Triphenylmethyl carbocation

Secondary alkyl free radical

Carbanion

Carbocation

Free radical

Carbene

${\rm{CH}}_3^ - > {1^ \circ } > {2^ \circ } > {3^ \circ }$

${3^ \circ } > {2^ \circ } > {1^ \circ } > {\rm{CH}}_3^ -$

${3^ \circ } > {1^ \circ } > {2^ \circ } > {\rm{CH}}_3^ -$

${2^ \circ } > {3^ \circ } > {1^ \circ } > {\rm{CH}}_3^ -$

$\% {\kern 1pt} {\kern 1pt} {\kern 1pt} {\rm{of}}{\kern 1pt} {\kern 1pt} {\kern 1pt} {\rm{N}} = \frac{{1.4{\kern 1pt} {\kern 1pt} V{\kern 1pt} {\kern 1pt} w}}{N}$

$\% {\kern 1pt} {\kern 1pt} {\rm{of}}{\kern 1pt} {\kern 1pt} {\rm{N}} = \frac{{1.4{\kern 1pt} {\kern 1pt} V{\kern 1pt} {\kern 1pt} N}}{w}$

$\% {\kern 1pt} {\kern 1pt} {\rm{of}}{\kern 1pt} {\kern 1pt} {\rm{N}} = \frac{{V{\kern 1pt} N{\kern 1pt} w}}{{1.8}}$

$\% {\kern 1pt} {\kern 1pt} {\rm{of}}{\kern 1pt} {\kern 1pt} {\rm{N}} = \frac{{1.4{\kern 1pt} {\kern 1pt} w{\kern 1pt} N}}{V}$

Pyramidal

Planar

Tetrahedral

Linear

${\rm{C}}{{\rm{H}}_3}{\rm{CH}}_2^ -$

${\rm{HC}} \equiv {{\rm{C}}^ - }$

${\left( {{{\rm{C}}_6}{{\rm{H}}_5}} \right)_3}{{\rm{C}}^ - }$

${\left( {{\rm{C}}{{\rm{H}}_3}} \right)_3}{{\rm{C}}^ - }$

Tertiary carbocations are more stable than secondary carbocations.

Resonance delocalizes the positive charge and increases carbocation stability.

Hyperconjugation contributes to the stability of carbocations.

Electron-withdrawing groups directly attached to the carbocation center increase its stability.

The bonds broken and formed

The reaction intermediates

The relative rates of discrete steps, especially the slowest one

All of the above

Carbanion

Carbocation

Free radical

Transition state

Free radical

Carbanion

Carbocation ion

Carbine

It has a positive charge on a carbon atom.

It has an unpaired electron on a carbon atom.

It has a negative charge on a carbon atom.

It is sp2 hybridized.