Melting wax evaporating gasoline freezing water these changes are all examples of a) nuclear changes. b) physical changes. c) chemical changes. d) energy consumption.

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B) physical changes.

Explanation:

A physical change is defined as a change in which there is alteration in shape, size and state etc. No new substance gets formed in these reactions.

A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.

A nuclear change is defined as a change in which a change in nuclear composition takes place.

Melting wax, evaporating gasoline  and freezing water  are all physical changes as they only involve change of state and no change in chemical or nuclear composition takes place.

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.

he would use the colour black