All weather that happens in Earth's atmosphere occurs in the troposphere. Choose the best two reasons for this. A) The troposphere is the atmospheric level closest to Earth's surface. B) Of all atmospheric levels, the troposphere contains the most water vapor. C) The troposphere has equal parts of nitrogen and oxygen, which creates clouds. D) The troposphere is the only level of atmosphere that is affected by gravity. E) The Sun's light controls the water cycle, and it only reaches the troposphere

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.