This set of Class 11 Chemistry Chapter 3 Multiple Choice Questions & Answers (MCQs) focuses on “Classification of Elements and Periodicity in Properties”. These MCQs are created based on the latest CBSE syllabus and the NCERT curriculum, offering valuable assistance for exam preparation.
1. __________ gave the idea for the first time to classify elements as per their properties.
a) Mendeleev
b) Dobereiner
c) Newland
d) John
View Answer
Explanation: In the early 1800s, a German chemist named Dobereiner came up with the idea of classifying elements as per their properties. LAter in 1829, he noticed a similarity in triads (a group of 3 elements). This is how he classified.
2. In triads, the average weight of the 1st and the 3rd element are equal to the second one.
a) True
b) False
View Answer
Explanation: As per Dobereiner Triads, the above statement”. In triads, the weight the 2nd element is about halfway between weights of 1st and 3rd elements.” For example, consider a triad of Li, Na, and K with atomic weight 7, 23 and 39 respectively.
3. Which of the following is not Dobereiner triad?
a) Li, Na, and K
b) He, Na and Ar
c) Ca, Sr and Ba
d) CL, Br and I
View Answer
Explanation: According to Dobereiner, in triads, the average weight the 1st and the 3rd element are equal to the second one. Li, Na, and K; Ca, Sr and Ba; CL, Br and I satisfy the above conditions. But He, Na and Ar don’t follow the law of Dobereiner Triads.
4. The property of every eight elements is similar to that of the 1st element. This is proposed by ___________
a) Thomson
b) Dobereiner
c) Mendeleev
d) John Alexander Newland
View Answer
Explanation: In the year 1865, an English chemist named John Alexander Newland proposed the law of octaves. It stated that when elements are arranged in their increasing atomic weights, the property of every eight elements is similar to that of the 1st element.
5. Newland’s law of Octaves is only valid until calcium.
a) False
b) True
View Answer
Explanation: Yes, the above statement is true. according to John Alexander Newland, when elements are arranged in their increasing atomic weights, the property of every eight elements is similar to that of 1st element. But it’s only true till calcium, so its failed.
6. According to Mendeleev’s periodic law, the periodic functions of the __________ are the properties of respective elements.
a) Atomic Weights
b) Atomic Number
c) Chemical properties
d) No of protons
View Answer
Explanation: According to Russian chemist named Dmitri Mendeleev who got the credits for the development of the modern periodic table, the periodic functions of the atomic weights are the properties of respective elements.
7. Eka Aluminium is _________
a) Germanium
b) Gallium
c) Silicon
d) Copper
View Answer
Explanation: At the time of Mendeleev, Gallium was not discovered. So he predicted Gallium’s properties and left a space for it, by naming it Eka Aluminium. The properties he predicted were almost the same as Gallium’s properties.
8. What are the atomic weights of Eka Silicon and Germanium?
a) 72, 72.6
b) 68, 70
c) 70, 72
d) 68, 72.6
View Answer
Explanation: At the time of Mendeleev, Germanium was not discovered. So he predicted Germanium’s properties and left a space for it, by naming it Eka Silicon. So he predicted Eka silicon’s atomic weight as 72, but the Germanium’s atomic weight is 72.6.
9. In Mendeleev’s periodic classification, what is the number of groups?
a) 12
b) 8
c) 7
d) 6
View Answer
Explanation: A Russian chemist named Dmitri Mendeleev classified elements based on chemical and physical properties in ascending order of their atomic weights. The number of groups was 8 and there were 12 series.
10. The ideal gases were in ____ group of Mendeleev’s periodic table.
a) 3rd
b) 4th
c) 1st
d) 2nd
View Answer
Explanation: Dmitri Mendeleev classified elements based on chemical and physical properties in ascending order of their atomic weights. Noble gases were placed in the first group of Mendeleev’s periodic table.
More MCQs on Class 11 Chemistry Chapter 3:
- Chapter 3 – Classification of Elements and Periodicity in Properties MCQ (Set 2)
- Chapter 3 – Classification of Elements and Periodicity in Properties MCQ (Set 3)
- Chapter 3 – Classification of Elements and Periodicity in Properties MCQ (Set 4)
- Chapter 3 – Classification of Elements and Periodicity in Properties MCQ (Set 5)
- Chapter 3 – Classification of Elements and Periodicity in Properties MCQ (Set 6)
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