- Potassium is a chemical element; it has symbol K (from Neo-Latin kalium) and atomic number 19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, which is easily removed to create an ion with a positive charge (which combines with anions to form salts). In nature, potassium occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-colored flame. It is found dissolved in seawater (which is 0.04% potassium by weight), and occurs in many minerals such as orthoclase, a common constituent of granites and other igneous rocks.
- Oceania (Wikipedia)
Oceania (UK: /ˌoʊsiˈɑːniə, ˌoʊʃi-, -ˈeɪn-/ OH-s(h)ee-AH-nee-ə, -AY-, US: /ˌoʊʃiˈæniə, -ˈɑːn-/ OH-shee-A(H)N-ee-ə) is a geographical region including Australasia, Melanesia, Micronesia, and Polynesia. Outside of the English-speaking world, Oceania is generally considered a continent, while Mainland Australia is regarded as its continental landmass. Spanning the Eastern and Western hemispheres, at the centre of the water hemisphere, Oceania is estimated to have a land area of about 9,000,000 square kilometres (3,500,000 sq mi) and a population of around 44.4 million as of 2022. Oceania is the smallest continent in land area and the second-least populated after Antarctica.