The electronic structure of a water molecule H2O can be described by the arrangement of its electrons in the atomic and molecular orbitals. In a water molecule, there are two hydrogen atoms and one oxygen atom.Oxygen has an atomic number of 8, so it has 8 electrons. Its electron configuration is 1s 2s 2p. Hydrogen has an atomic number of 1, so it has 1 electron. Its electron configuration is 1s.In the formation of a water molecule, the 1s orbital of each hydrogen atom overlaps with the 2p orbitals of the oxygen atom, forming two sigma bonds. These sigma bonds are formed by the head-on overlap of the orbitals and are called sp hybrid orbitals. The remaining two 2p orbitals on the oxygen atom are filled with lone pair electrons, which do not participate in bonding.The molecular orbitals involved in the formation of a water molecule are:1. Two sigma bonding orbitals: These are formed by the overlap of the 1s orbitals of the hydrogen atoms with the sp hybrid orbitals of the oxygen atom.2. Two non-bonding orbitals: These are the remaining 2p orbitals on the oxygen atom, which contain the lone pair electrons.In summary, the electronic structure of a water molecule consists of two bonding orbitals formed by the overlap of the hydrogen 1s orbitals with the oxygen sp hybrid orbitals, and two non-bonding orbitals containing the lone pair electrons on the oxygen atom.