Physical changes are changes affecting the form of a chemical substance, but not it's chemical composition.
Basically, the answer for this would be N or NITROGEN. If we combine nitrogen with chlorine, what happens is that, it can attract more chlorine electrons towards itself. The reason is that, nitrogen is considered more electronegative compared to chlorine. So best answer for this is the first option.
<span>Within the carbon monoxide molecule, the single carbon and single oxygen atoms are joined through a triple bond. This triple bond is comprised of a dative covalent bond and two additional covalent bonds. This forms the most chemically simple of the oxocarbons.</span>
