B. The atomic number. This is because the atomic number is the same as the number of protons an element has, and the number of protons defines an element.
I am pretty sure the answer is 6.25 molecules
See picture for explanation
<span>It becomes an </span>ion<span>. An atom that gains a negative electron, it becomes a negative </span>ion<span>. If it loses an electron it becomes a positive </span>ion<span>.</span>
Hope this helps!
"The other halogens are not as electronegative and so other hydrogen halides cannot form hydrogen bonds between molecules. Only London Forces are formed. - Therefore more energy is required to break the intermolecular forces in HF than the other hydrogen halides and so it has a higher boiling point."
not a hack link, just stating where i got your answer from! -
https://www.mytutor.co.uk/answers/17558/A-Level/Chemistry/Explain-the-unusually-high-boiling-point-of-HF/
