Answer:
They expressed it as rate of change in concentration of reactants or products in a chemical reaction
Because society has shaped our mind on what we shall think about things
All compounds are molecules because a molecule is 2 or more substances/elements combined and a compound is 2 or more elements combined. But not all molecules are elements because some molecules are just combined substances with no elements combined at all.
What happens when chlorine form an ion is that it gains an electron and has an octet in its outer shell ( answer A)
<u><em> Explanation</em></u>
<u><em> </em></u>Chlorine is is in atomic number 17 in periodic table.
The electron configuration of chlorine is 1S2 2S2 2P6 3S2 3P5 or[Ne]3S2 3p5 or 2.8.7.
chlorine therefore has 7 valence electron therefore it gain 1 electron to form Cl- ( ion)
Cl- has 8 electron in its outer shell ( it obeys octet rule of eight valence in outer shell.