Question

Which are the elements that occupy the peak position in the Lother Meyer curve?
A. Alkali metals
B. Highly electropositive elements
C. Elements having large atomic volumes
D. All of the above

Answer 1

Hint: A German chemist, named Lother Meyer worked with Mendeleev and Robert Bunsen to formulate the first periodic table of chemical elements. He in 1869 studied extensively the atomic volumes of a large number of elements. He plotted his observations in a graphical representation where the atomic number was taken as the X-axis and the atomic volume was taken as the Y-axis. In this graphical representation, he obtained a curve which he termed as an atomic volume curve.
Step-by-step observation:
Step 1
The volume occupied by one gram atom of that element is known as the Atomic volume of that element.
Step 2
In the atomic volume curve, there were many shape peaks and broad minimas which reflect excellent periodicity in the atomic volumes of those elements.
Step 3
The observation from the atomic volume curve are listed as follows:
The first element of the period i.e., alkali metals like Li, Na, K occupies the peak position of the curve.
The least reactive transition metals like Fe, Mn, Co, Ni occupy the minimas of the curve.
The electronegative elements occupy the ascending slope of the atomic volume curve.
The electropositive elements occupy the descending slope of the atomic volume curve.
The elements like C, Si, Fe which occupy the descending slope of the curve have high melting points.
The elements belonging to a particular group are placed identically in the curve.
Step 4
From the above observations, we can understand that the peak of the atomic volume curve given by Lother Meyer is occupied by the alkali metals, which have the highest atomic volume in a particular period, and the highest electropositive behavior.

Hence, option d), all of the above is the correct judgment for the given statement.

Note: Atomic size is often confused with atomic volume. The atomic size which is also known as the atomic radius is the distance from the center of the nucleus to the outermost shell of the electrons whereas atomic volume is the volume occupied by one gram atom of that element.