Why do highly reactive metals react vigorously with water?

Highly reactive metals react vigorously with water due to their strong tendency to lose electrons and form positive ions.

Highly reactive metals, such as potassium, sodium, and calcium, belong to the group 1 and 2 of the periodic table, also known as alkali and alkaline earth metals respectively. These metals have one or two electrons in their outermost shell, which they are eager to lose in order to achieve a stable electron configuration. This eagerness to lose electrons makes them highly reactive.

When these metals come into contact with water, they readily donate their outermost electrons to the water molecules. This process is known as oxidation, and it results in the formation of metal hydroxide and hydrogen gas. The reaction is exothermic, meaning it releases energy in the form of heat and light. This is why you often see a vigorous reaction, with the metal fizzing and moving around, and sometimes even catching fire.

For example, when sodium (Na) reacts with water (H2O), it forms sodium hydroxide (NaOH) and hydrogen gas (H2). The reaction can be represented as follows: 2Na + 2H2O → 2NaOH + H2. The reaction is so exothermic that the hydrogen gas produced often ignites, causing a flame.

The reactivity of these metals increases down the group. This is because the outermost electrons are further from the nucleus and are therefore less tightly held, making them easier to lose. So, potassium is more reactive than sodium, and sodium is more reactive than lithium.

In conclusion, the vigorous reaction of highly reactive metals with water is due to their strong tendency to lose electrons, their formation of positive ions, and the exothermic nature of the reaction.