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How is potassium’s electron configuration related to its reactivity?

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A periodic table element box for potassium shows atomic number 19, symbol K, atomic weight 39.0983, electron configuration [Ar]4s1, and name potassium. Icons indicate it is an alkali metal, solid at room temperature, body-centered cubic crystal structure, and has strongly basic higher-valence oxides. A key explains the symbols for alkali metals, solid state, body-centered cubic structure, and strong basicity. — potassium Properties of potassium.

Potassium’s high chemical reactivity is directly linked to its electron configuration, which is $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{1}$ (or 2-8-8-1).1

As an alkali metal in Group 1 of the periodic table, potassium possesses a single electron in its outermost valence shell. This configuration is highly unstable because the atom can achieve a more stable, noble-gas-like electronic structure by easily losing that lone $4 s$ valence electron.123

Because this outer electron is loosely held, potassium readily donates it to other elements with higher electron affinity, such as halogens or oxygen. This tendency to lose an electron results in the formation of stable, singly charged positive ions ( $K^{+}$ ) and drives the element's vigorous reactivity with substances like water and air.423