When a material is heated, the kinetic energy of that material increases and its atoms and molecules move about more. This means that each atom will take up more space due to its movement so the material will expand. ... Some metals expand more than others due to differences in the forces between the atoms / molecules.
2K + Cl₂ ⇒ 2KCl
2Ca + O₂ ⇒ 2CaO
the modern atomic model shows that electrons are located in a predicted area but cannot be identified in a specific point
Hope this helps :)
