Which of the following metals would be the least safe to drop in water? Why?
Metals have excess electrons - that is, they can contribute electrons much easier than non-metals.
All physical systems try to achieve minimal energy state. This means that elements will try, via chemical reactions, to achieve a situation in which the new outer electronic shell is filled with electrons.
This means that the metals will try to get rid of their outer electrons. However, once a single electron is ejected the atom (which is now an ion) becomes more positively ...
This solution explains which, out of five given metals, is the least safe to drop in water, addressing outer shell electrons and minimal energy states.