Question

How could the modern periodic table remove various anomalies from Mendeleev's periodic table?

Answer 1

Mendeleev's Periodic Table

1. Mendeleev claimed the famous periodic law that “Element properties are periodic functions of their atomic weight”
2. Mendeleev placed elements in order of their atomic weight in the form of a table known as the periodic table of Mendeleev.
3. Mendeleev's periodic table contains vertical columns called “groups” and horizontal rows called Periods.

Modern Periodic Table

1. In the modern periodic table, elements are arranged in increasing order of their atomic number. This removes the anomaly regarding certain pairs of elements in Mendeleev's periodic table which are arranged in order of their atomic weights.
2. The atomic number of cobalt is 27 and nickel is 28 hence, cobalt will come before nickel even though its atomic number is higher.
3. All isotopes of the same elements have different masses but the same atomic number they are placed in the same position in the modern periodic table.

Therefore, by arranging elements in order of increasing atomic number, the modern periodic table removes the anomaly of Mendeleev's periodic table which arranges elements in order of their atomic mass.