In this compound, the oxygen is in the middle of the two hydrogen atoms, which are off to one side of the oxygen, forming an angular shape. The hydrogens do not form a straight line with the oxygen, because the oxygen has a couple of extra electron pairs that need some room too. The hydrogens are each connected to the oxygen with an electron pair, making a total of 4 pairs (or 8 electrons). When four pairs of electrons surround an atom, they spread out as much as they can, into a tetrahedral formation. In water, only two of the electron pairs have atoms connected, but the other two need room too.

Compare this structure with that of Si₄F in problem 2, and look for a molecular geometry quiz soon.

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