NUMBER of electorn in 18ml water (solidity is 1gm/ml)

I haven't hear solidity used in connection with H2O before; are you trying to say density since density is 1 g/mL.

mass H2O = volume x density = 18 mL x 1 g/mL = 18 grams.
mols H2O = g/molar mass = 18/18 = 1 mol
There are 6.02E23 molecules in 1 mol.
There are 16 electrons in 1 mole of the O atoms and 2 electrons in the H atoms making 18 electrons per one water molecules.
18 electrons/molecule x 6.02E23 molecules = ? total electrons.