Model of a single molecule of water, showing the arrangement of the two atoms of hydrogen (white balls) and one oxygen atom (red) that comprise the molecule. The dark grey sticks" represent covalent bonds formed by single electrons provided by both atoms; each hydrogen provides 1 electron to share with 1 of 2 provided by the oxygen atom. Each bond is composed of a region of negative charge. The oxygen atom also possesses 2 further pairs of electrons whose presence causes the bent, V-shape of the water molecule, since the so-called "lone pairs" of electrons (also centres of negative charge) are able to exert a greater repelling effect than bonded electrons."