Topic: Classification of Elements and Periodicity in Properties (Test 1)



Topic: Classification of Elements and Periodicity in Properties
Q.1
Dmitri Mendeleev (1834-1907) and the German chemist, Lothar Meyer (1830-1895) proposed arranging elements in
A. decreasing order of their atomic weights
B. increasing order of their atomic numbers
C. increasing order of their atomic weights
D. decreasing order of their atomic numbers
Answer : Option C
Explaination / Solution:

If the elements are arranged in the order of their increasing atomic weights, after a regular interval similiar properties of elements are repeated.

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Q.2
Mendeleev 'Periodic Law' states that
A. The properties of the elements are a periodic function of the number of neutrons.
B. The properties of the elements are the periodic function of their atomic weights.
C. The properties of the elements are a periodic function of their atomic number.
D. The properties of the elements are a periodic function of the number of electrons.
Answer : Option B
Explaination / Solution:

If the elements are arranged in the order of their increasing atomic weights, after a regular interval similiar properties of elements are repeated.

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Q.3
Mendeleev arranged elements in a periodic table in order of their increasing atomic weights in such a way that the elements with similar properties occupies
A. the positions on the top left to bottom right diagonal
B. the positions on the bottom left to top right diagonal
C. the same vertical column or group.
D. the same Horizontal row or series
Answer : Option C
Explaination / Solution:

Mendeleev arranged elements in horizontal rows and vertical columns of a table in order of their increasing atomic weights in such a way that the elements with similar properties occupied the same vertical column or group.This is because properties of elements are reapting after regular interval.

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Q.4
Mendeleev relied on the similarities in the empirical formulas and properties of the compounds formed by the elements. He realized that some of the elements did not fit in with his scheme of classification if the order of atomic weight was strictly followed. He therefore
A. placed the elements with same atomic weight together
B. placed the elements with same atomic number together
C. amended the periodic law
D. Xplaced the elements with similar properties together
Answer : Option D
Explaination / Solution:

Mendeleev placed the elements with similar properties together

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Q.5
Mendeleev proposed that some of the elements were still undiscovered and, therefore, left several gaps in the table. He left the gap under aluminium and a gap under silicon, and called these elements Eka-Aluminium and Eka-Silicon. These were later discovered and named
A. Gallium and Godolinium respectively
B. Barium and Germanium respectively
C. Gallium and Germanium respectively
D. Mendelivium and Germanium respectively
Answer : Option C
Explaination / Solution:

Mendeleev arranged the elements according to their atomic weights. He corrected the atomic weights of few exisiting elements to explain their chemical and physical behaviour. Moreover, he felt that few elements are still to be discovered, so he left empty spaces for them in his periodic table. Two such elements whose properties he predicted; and were later discovered are Gallium and Germanium respectively.

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Q.6
Modern Periodic Law can be stated as:
A. The physical and chemical properties of the elements are independent of their atomic numbers.
B. The physical and chemical properties of the elements are periodic functions of their neutron numbers.
C. The physical and chemical properties of the elements are periodic functions of their atomic masses.
D. The physical and chemical properties of the elements are periodic functions of their atomic numbers.
Answer : Option D
Explaination / Solution:

Modern Periodic Law can be stated that the physical and chemical properties of the elements are periodic functions of their atomic numbers

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Q.7
It is now recognized that the ‘Modern Periodic Law’ is essentially the consequence of
A. periodic variation in electronic configurations
B. periodic variations in the element lattice
C. periodic variation in chemical bonds
D. periodic variation in chemical properties
Answer : Option A
Explaination / Solution:

Modern Periodic Law of element may be defined as the Physical and chemical properties of the elements are periodic functions of their atomic numbers.It means, when the elements are arranged in the order of their increasing atomic numbers, it is observed that the elements of similar properties recur at regular intervals or periodically. As a result of this, the elements fall in certain groups and lead to an arrangement called the modern periodic table of elements. It must be noted that elements are arranged in the periodic table in order of atomic numbers because atomic number is the most fundamental property of an element. The systematic arrangement of elements in modern periodic table according their atomic number helps in justification of isotopes of elements at one place.

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Q.8
In the modern periodic table
A. The horizontal rows are called groups and the vertical columns, periods
B. The horizontal rows are called periods and the vertical columns, groups.
C. The horizontal rows are called periods and the vertical columns, series.
D. The horizontal rows are called series and the vertical columns, groups.
Answer : Option B
Explaination / Solution:

In modern periodic table, the elements are arranged in the increasing order of their atomic number. It contains 7 horizontal rows called periods and 18 vertical columns called groups.

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Q.9
According to the recommendation of International Union of Pure and Applied Chemistry (IUPAC), the groups in the modern periodic table are numbered from
A. 1 to 8
B. 1 to 10
C. 1 to 18
D. 1 to 12
Answer : Option C
Explaination / Solution:

The groups are numbered from 1 to 18; where group 1 is alkali metal group and group 18 is for the noble gases.

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Q.10
Choose one of the following in the order of increasing radii:
A. I+ < I- < I
B. I < I+ < I-
C. I- > I > I+
D. I- < I+ < I
Answer : Option C
Explaination / Solution:

Size of anion is greater than the size of parent atom and size of cation. As the –ve charge of anion increases ionic radii increases due to decrease in the effective nuclear charge and vice versa.

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