Is a water molecule neutral?
“The shape of a water molecule is also a tetrahedron. Oxygen has six valence electrons and two “holes,” thus can bond with two hydrogens. Therefore, the chemical formula for water is H2O. Oxygen’s other four valence electrons, in two pairs, are not bonded to any other atoms, thus these are referred to as unshared pairs of electrons. Oxygen shares electrons with hydrogen, but pulls just a little harder on the electrons. The electrons are just a little closer to the oxygen than the hydrogens, so this is called a polar covalent bond. Note that even though the molecule as a whole is electrically neutral (the + and – charges balance), the ends of the molecule where the hydrogen nuclei are (which contain only a proton) have a sort-of positive charge, and the ends of the molecule by the unshared pairs of electrons are sort-of negative. The sort-of positive ends on one water molecule are attracted to the sort-of negative ends on another water molecule. This is called hydrogen bonding.
