It means is where something is removed or erased completely or something unwanted or unpleasant.
Hope this helps and the right meaning of expunge.
Atoms of oxygen are electronegative and attract the shared electrons in their covalent bonds.
Since particles are closer together, solids conduct heat better than liquids or gases. Conduction moves heat through a material. It keeps a fire going by spreading the heat through solid material. Radiation is a method of heat transfer that does not require particles to carry the heat energy.
Chlorine will have the slowest rate of diffusion because it has the highest relative molecular mass of 71 followed by O₂ with 32, then Neon 20 then He with 2
The rate of diffusion of a gas is inversely proportional to the square root of its relative molecular mass.
