Question

Which prediction is/are correct according to the Lothar Meyer’s curve?
(this question has multiple correct answers)
A. Each peak of the curve is occupied by the alkali metals.
B. Alkaline earth metals occupy ascending positions of the curve.
C. Atomic volume increases first and then decreases in a period (which is defined later) in Lothar Meyer’s curve.
D. Identically placed elements in the atomic volume vs mass curve occur in the same period in the periodic table.

Answer 1

Hint: To solve this question we first need to learn about the Lothar- Meyer‘s curve in which the elements are arranged in accordance with their atomic volume and the atomic weights.

Complete step by step solution:
Lothar Meyer was a German chemist. In 1869 he studied the physical properties of various elements and plotted a graph between the atomic volume and the atomic weights of the elements. From the graph he made the observation that the elements with similar properties had similar positions on the curve and arrived at the conclusion that the physical properties of the elements are a periodic function of their atomic weights.

Some of the properties of the curve are:
-The most electropositive alkali metals were present at the peak of the curves while the alkaline earth metals filled the descending positions on the curve.
-Halogens were present at the ascending positions on the curve.
-Noble gases are present just before the alkali elements.

1. The first option (a) each peak of the curve is occupied by the alkali metals is true except for Helium.
2. The second option (b) Alkaline earth metals occupy ascending positions of the curve is wrong since the alkaline earth metals occupy the descending positions on the curve.
3. The third option (c) Atomic volume increases first and then decreases in a period (which is defined later) in Lothar Meyer’s curve is also false since the atomic volume first decreases and then increases in a period.
4. The fourth option (d) Identically placed elements in the atomic volume vs mass curve occur in the same period in the periodic table is also false since they occur in the same group of the periodic table.

Therefore the correct answer is (a) Each peak of the curve is occupied by the alkali metals.

Note: Hydrogen and the Helium are the exceptions to the rules. Each fall and rise in the graph denotes the elements belonging to a certain period.