The law of thermodynamics states that when two objects of different temperature are in contact, heat energy will flow from the hotter to the cooler object.

Second.

Explanation:

There are four types or kinds of the laws of thermodynamics, but in this question we are actually considering the second law of thermodynamics.

The second law of thermodynamics, in a simple sense means that energies can flow in an equilibrate manner. It can also be stated as the total entropy of the universe. The second law is normal refer to as Law concerning Entropy.

Thus, filling the gap in the Question above. Note that the word written in capital letters is the missing word.

"The SECOND law of thermodynamics states that when two objects of different temperature are in contact, heat energy will flow from the hotter to the cooler object."

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.