Question 3
In a hydrogen fluoride molecule, which atom carries the δ− charge, and why?
The right answer is the one marked above.
The fluorine atom, because it is more electronegative. It pulls the shared pair closer to itself, so a small excess of negative charge builds up on the fluorine end.
Size is not what decides this. Total proton count is not either — what matters is the pull on the bonding pair, not the size of the nucleus. And the molecule being neutral overall does not stop charge from being unevenly spread within it.