AP BIOLOGY

Detailed explanation-1: -The unequal sharing of electrons between the atoms and the unsymmetrical shape of the molecule means that a water molecule has two poles-a positive charge on the hydrogen pole (side) and a negative charge on the oxygen pole (side). We say that the water molecule is electrically polar.

Detailed explanation-2: -In the covalent bond between oxygen and hydrogen, the oxygen atom attracts electrons a bit more strongly than the hydrogen atoms. The unequal sharing of electrons gives the water molecule a slight negative charge near its oxygen atom and a slight positive charge near its hydrogen atoms.

Detailed explanation-3: -Electrons in a polar covalent bond are unequally shared between the two bonded atoms, which results in partial positive and negative charges. The separation of the partial charges creates a dipole. The word dipole means two poles: the separated partial positive and negative charges.

Detailed explanation-4: -Because oxygen is more electronegative-electron-greedy-than hydrogen, the Ostart text, O, end text atom hogs electrons and keeps them away from the Hstart text, H, end text atoms. This gives the oxygen end of the water molecule a partial negative charge, while the hydrogen end has a partial positive charge.

Detailed explanation-5: -Thus, the electronegativity difference between oxygen and hydrogen atoms causes polarity in H2O molecules.