The space filling model of the water is shown in the figure given below in the figure, where δ+/ δ- represent the partial charge.
The water molecule consist of 2 hydrogen and one oxygen atom. The oxygen atom is the central molecule and the other two hydrogen are bind to the oxygen atom. The sizeof the oxygen is much bigger than the hydrogen and is more electronegative than hydrogen. Due to the elctronegativity, the oxygen pulls the electron and gain slight negative charge and the hydrogen gain slight positive charge and result in polarity.
