Is the atom indicated with an arrow nucleophilic, electrophilic, acidic, more than one of these choices, or none of these choices? (For purposes of this question, acidic is defined as pKa ≤ 25.)

The boiling point of propanoic acid is higher than that of 1-butanol because: propanoic acid has a higher molecular weight than 1-butanol. propanoic acid is more soluble in water than 1-butanol. propanoic acid is a better hydrogen bond donor than 1-butanol. propanoic acid forms hydrogen bonded dimers and 1-butanol does not. 1-butanol forms hydrogen bonded dimers and propanoic acid does not.

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit

What atom has the largest atomic radius