In class, I learned that when $\ce{NaCl}$ is dissolved in water, the partially negative oxygen part of the water molecules surround the $\ce{Na+}$ ion and energy is given off (hydration enthalpy)

Likewise, when a transition metal ion like $\ce{Fe^2+}$ is dissolved in water, water molecules surround the ion. However, in this case, we say that a complex ion is formed.

Can someone please tell if there is really a difference in the two cases and if yes, could someone specify them.


Question: Selecting multiple icons in Finder using the keyboard?
Answer: The answer, it turns out, is fairly unintuitive.


Select the last item (the PSD).
Press Shift + Up.
Hold Shift and press Right repeatedly until you get the selection you want.