SSC MTS 2026 PYQ — Question 65

Correct Answer:
Option 1 (Similarity of Chemical Properties)

Explanation:
When developing his Periodic Table, Dmitri Mendeleev arranged the elements in increasing order of their atomic mass. Furthermore, his primary focus was on the similarity of elements' chemical properties. He observed that elements with similar chemical and physical properties repeated after a certain interval. Therefore, he placed elements with similar properties in the same vertical column or group.

Additional Facts:
Atomic Mass: Mendeleev's Periodic Table was based on atomic mass, while the modern Periodic Table is based on atomic number.
Blank Spaces: Mendeleev left some blank spaces in his table and predicted the properties of elements that had not yet been discovered (such as eka-aluminum, which later became gallium).
Position of Hydrogen: A major shortcoming of Mendeleev's table was that he failed to assign a specific position to hydrogen.

Possible questions for upcoming exams:
Who is considered the father of the Modern Periodic Table? (Answer: Henry Moseley)
On what basis did Mendeleev arrange the elements in his periodic table?
(Answer: On the basis of increasing atomic mass and chemical properties)
How many groups and periods were there in Mendeleev's periodic table? (Answer: 8 groups and 6 periods)