When propane burns, heat and light are produced. Where does this energy come from?

It releases energy from the breaking of bonds during its combulsion stages.

Explanation:

(This expanation is not from me, its from qizzlet.com. but the anserw is made by me)

When propane burns, heat and light are produced. Where does this energy come from? The energy comes from, the breaking of the bonds and it is being released.

beta decay is the answer

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.