Question

Which of the following does not react with water?
A.Sodium ions
B.Sodium atoms
C.Potassium ions
D.Both A and C

Answer 1

Water reactive substances are those that spontaneously undergo a chemical reaction with water as they are highly reducing in nature. Some of the examples are alkaline earth metals, alkali metals, sodium through barium etc.

Complete step by step answer:
-Alkali metals belong to the s- block elements occupying the leftmost side of the periodic table. In general, they are basic or alkaline in nature. These compounds are known as alkali metals because when they react with water, they usually form alkalis which are nothing but strong bases that can easily neutralize acids. Moreover, they have the lowest density because of the largest radius and volume.
-Now, moving further to alkaline earth metals. These are the elements that correspond to groups of the modern periodic table. These elements have more density and are harder than alkali metals. Moreover, the smaller ions have higher charge density and can be solvated by more water molecules.
-Further, the sodium and potassium ions do not react with water. This is due to the fact that they have already lost the electron and are therefore much more stable. They don’t tend to lose another electron and they also do not try to get that lost electron back so there is no tendency for them to react further.

Hence, option D is correct.

Note:
Sodium has a strong metallic luster and is very analogous to silver in color. It is a reactive, soft metal with a low melting point. Moreover, sodium compounds soon tarnish on exposure to the air though less rapidly than potassium.