Original Resolution: 480x222 Https Encrypted Tbn0 Gstatic Com Images Q Tbn And9gcsiivegpjqtmklkikj94ec3v0doatidfg1xzw Usqp Cau The diagram opposite shows the lewis structure for the water molecule, h2o in most molecules, like ch4, bf3 and sf6, the central atom is the first one in the formula.