Question

The increasing order of the density of alkali metals :
\begin{array}{*{20}{l}} {(A)Li{\text{ }} < {\text{ }}K{\text{ }} < {\text{ }}Na{\text{ }} < {\text{ }}Rb{\text{ }} < {\text{ }}Cs} \\\ \; \\\ {(B)Li{\text{ }} < {\text{ }}Na{\text{ }} < {\text{ }}K{\text{ }} < {\text{ }}Rb{\text{ }} < {\text{ }}Cs} \\\ \; \\\ {(C)Cs{\text{ }} < {\text{ }}Rb{\text{ }} < {\text{ }}Na{\text{ }} < {\text{ }}K{\text{ }} < {\text{ }}Li} \\\ \; \\\ {(D)Cs{\text{ }} < {\text{ }}Rb{\text{ }} < {\text{ }}K{\text{ }} < {\text{ }}Na{\text{ }} < {\text{ }}Li} \\\ \; \\\ {(E)Li{\text{ }} < {\text{ }}Na{\text{ }} < {\text{ }}Rb{\text{ }} < {\text{ }}K{\text{ }} < {\text{ }}Cs} \\\ \; \end{array}

Answer 1

There is an inconsistency in what we would hope to be the standard pattern because of the metal making the oddity being referred to have a lot more prominent volume than that of its replacement. In light of this thought, attempt and sort out the right request here.

Complete step by step solution:
Allow us first to attempt to comprehend what the soluble base metals truly are prior to attempting to decide the request for their densities. A soluble base metal is one of any of the six synthetic components that make up Group 1 (la) of the intermittent table - in particular, lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). The salt metals are purported in light of the fact that they respond with water structures antacids (i.e., solid bases equipped for killing acids).
Allow us currently to attempt to decide the request for their densities. The salt metals all have a similar gem structure (body-focused cubic) and accordingly the lone pertinent components are the quantity of iotas that can find a way into a specific volume and the mass of one of the particles since thickness is characterized as mass per unit volume. The principal factor relies upon the volume of the particle and in this manner the nuclear range, which increments going down the gathering; consequently, the volume of an antacid metal molecule increments going down the gathering. The mass of a salt metal particle likewise increments going down the gathering.
Accordingly, the pattern for the densities of the antacid metals relies upon their nuclear loads and nuclear radii; if figures for these two components are known, the proportions between the densities of the salt metals would then be able to be determined. The resultant pattern is that the densities of the soluble base metals increment down the table, with a special case at potassium because of an abnormal expansion in the nuclear size of potassium. In this manner, we can securely presume that the right expanding request of the thickness of salt metals is given by alternative a).
Hance correct option is (B).

Note:
Due to having the most reduced nuclear weight and the biggest nuclear range of the multitude of components in their periods, the soluble base metals are the un-thick metals in the intermittent table with Lithium, Sodium, and Potassium being the solitary three metals in the occasional table that are less thick than water. Indeed, lithium is the un-thick known strong at room temperature.