(1) Force of attraction between the particles of the chalk is weak.
(2) It is easy to break, but we can’t join.
(3) To join two materials we need to let the molecules of two get near enough for the coulomb forces to start acting.
(4) That’s why any solid keeps its shape.
(5) Liquids can’t keep its shape because the molecular distance in liquids is too large for this action.
