when light enters the medium of a glass prism from air, the light slows down / speeds up. the speed of each wavelength changes by a different amount. these differences of speed cause different wavelengths of light to refract/ reflect by different amounts when the light hits a surface at an angle, and that's why we see separate colors of light. the greater the change in speed between two media, the greater / lesser the refraction of a light wave. so light moving from air to glass will refract more / less than light moving from water to glass

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.

have a great day because if you dont you and i will be sad