<p><strong>Noun</strong></p><ul><li>Chemistry</li><li>A silvery-white metallic element</li><li>Oxidizes rapidly in the air</li><li>Compounds used as fertilizer</li><li>Compounds used in special hard glasses</li><li>Symbol: K</li><li>Atomic number: 19</li><li>Atomic mass: 39.102</li><li>Density: 0.86 at 20°C</li></ul>