Evaporation in molecular view

In water,particles are moving with a wide range of speeds.They bump into each other,and some gain kinetic energy while others lose KE.Some of the particles at the liquid surface may gain enough KE to escape into the spave above the water,and becomes particles of vapour
Futher explannation:In solid state,particles are close together and stayed a fixed position.However in liquid state,particles are not in fixed position.Each partcile can move from one place to another.When the particles collides with each other,by conservation of momentum,some might gain speed and obtains a higher kinetic energy.

There are water molecules surrounding each other inside the liquid
water but the layer between water & air is quite different. They can
move more freely, as the electron attraction is imbalance in this
interface. Once the molecules gain enough energy, they can break
through the attraction of bonding of other water molecule, hence
evaporation can take place.