the electron density of pi bonds are located above and below the line connecting the nuclei of the atoms bonded

Alkyl groups are electron donating because they have a lower electronegativity than the atoms in the pi system (such as carbon or nitrogen). The alkyl group donates electron density to the pi system through its sigma bonds, thereby increasing the electron density in the pi system. This electron donation stabilizes the pi system and can affect its reactivity.

The decolonization of pi electron in the benzene rings are usually helpful in the appearance of the color in dyes as a result of substituted aromatic rings which are usually complex.

mass of proton is 6 x pi raised to power 5 times mass of electron

Together they form a chemical bond.A sigma or pi bond