The modern periodic table is based on: MCQ with Answer and Explanation

The modern periodic table is based on:
A. Mass number
B. Atomic mass
C. Number of neutrons
D. Atomic number
Answer: Option D
Solution (By JKSSB Mock Tests)
The modern periodic law states that properties of elements are periodic functions of their atomic numbers (number of protons). This was established by Henry Moseley. Mendeleev's original table used atomic mass, but the modern table resolves anomalies by ordering by atomic number.

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More chemistry Questions

Question #1
Washing soda is:
A. NaOH
B. CaOCl₂
C. NaHCO₃
D. Na₂CO₃·10H₂O

Correct Answer: Option D


Explanation:
Washing soda is sodium carbonate decahydrate (Na₂CO₃·10H₂O). Baking soda is NaHCO₃. Caustic soda is NaOH. Bleaching powder is CaOCl₂.

This question belongs to: Science chemistry
Question #2
The mass of a substance deposited at the cathode is directly proportional to the:
A. Quantity of electricity passed
B. All of the above
C. Time
D. Current

Correct Answer: Option B


Explanation:
According to Faraday's First Law of Electrolysis, the mass (m) of a substance deposited at an electrode is directly proportional to the total quantity of electricity (Q) passed through the electrolyte. Since Q = Current (I) × Time (t), the mass is directly proportional to both the current and the time.

This question belongs to: Science chemistry
Question #3
Washing soda (Na₂CO₃·10H₂O) is obtained by:
A. Heating baking soda
B. Reaction of NaCl with CaCO₃
C. Electrolysis of brine
D. Recrystallization of sodium carbonate from its aqueous solution

Correct Answer: Option D


Explanation:
Sodium carbonate (soda ash) is dissolved in water and crystallized to obtain washing soda. Heating baking soda gives anhydrous sodium carbonate. Brine electrolysis gives NaOH, Cl₂, H₂. Solvay process makes Na₂CO₃.

This question belongs to: Science chemistry