<span>The </span>octet rule<span> is a chemical </span>rule<span> of thumb that reflects observation that atoms of main-group elements tend to combine in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.
Hope this helps</span>
Any substance changes to another substance that means the change of the physical property. Like water () has different state which changes as the temperature changes. It remain as liquid in the room temperature, in solid form at or below 0°C and vapor phase on or above 100°C. But in all the stage or phase of the substance the composition of the water i.e. remains. Thus the chemical property remains fixed when a substance change to other substance.
I don’t really have a clear answer for you but this might help
Statement B is true because atoms are single particles that come together to form compounds and molecules.
