Write the equality and conversion factors, and identify the numbers as exact or give the number of significant figures for which of the following:A. The Daily Value (DV) for iodine is 150 mcg. B. The nitrate level in well water was 32 ppm. C. Gold jewelary contains 58% gold by mass. D. The price of a litre of milk is $1.65.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

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.