What makes some metals more reactive than others?

The reactivity of metals is determined by the ease with which they lose electrons to form positive ions.

In more detail, the reactivity of a metal is directly related to its ability to lose electrons and form positive ions, a process known as oxidation. This is determined by the metal's electron configuration, specifically the number of electrons in its outermost shell. Metals with only one or two electrons in their outer shell tend to be more reactive because these electrons can be lost more easily. This is why group 1 and 2 metals in the periodic table, such as lithium, sodium, potassium, magnesium and calcium, are highly reactive.

The energy required to remove an electron from an atom is called ionisation energy. Metals with lower ionisation energies are more reactive because less energy is needed to remove their outermost electron. For example, francium, at the bottom of group 1, has the lowest ionisation energy of all the metals and is therefore the most reactive.

The reactivity of metals also depends on their position in the reactivity series, a list of metals ranked by their reactivity from most to least. This series is based on observations of how metals react with water, acid and oxygen. Metals at the top of the series, such as potassium and sodium, react violently with these substances, while those at the bottom, like gold and platinum, are virtually unreactive.

In summary, the reactivity of metals is determined by their electron configuration and ionisation energy, with more reactive metals having fewer electrons in their outer shell and lower ionisation energies. This is reflected in their position in the reactivity series.