Consider thiol anion $\left({\mathrm{RS}}^{\mathrm{\Theta }}\right)$ and alkoxy anion $\left({\mathrm{RO}}^{\mathrm{\Theta }}\right)$.

Which of the following statements is correct?

Nucleophilic strength depends on the electronegativity of the atom. Lower the electronegativity of an atom, larger the nucleophilic strength of an atom and more readily it will donate electrons to the electrophilic (${\mathrm{e}}^{-}$deficient) species. Since, electronegativity decreases down the group, thus
nucleophilic strength increases down the group. Hence, ${\mathrm{RS}}^{-}$ is more nucleophilic than ${\mathrm{RO}}^{-}$ due to less electronegativity of S than O. On the other hand, basic strength of an atom depends upon the tendency to accept a proton more readily. Since, $\mathrm{O}-\mathrm{H}$ bond is longer than $\mathrm{S}-\mathrm{H}$ bond, thus ${\mathrm{RO}}^{-}$ has a greater tendency to accept a proton than ${\mathrm{RS}}^{-}$

Thus, basic strength of the central atom decreases down the group.
Hence, ${\mathrm{RS}}^{-}$ is more nucleophilic but less basic than ${\mathrm{RO}}^{-}$.