MCQ Questions for Class 10 Chemistry Periodic Classification Of Elements Quiz 4

How does number of valence electrons vary on moving from left to right In the first period of a periodic table?

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0
0%
1
0%
2
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3

Which of the following elements is a metalloid?

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Tin
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Aluminium
0%
Silicon
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Zinc

Explanation

Hint: Metalloids are present in the $p$ block which separates metals from nonmetals.

Explanation :

· Metalloids depict properties intermediate between metals and non-metals.

· The six metalloids are known as boron ( $B$ ), silicon ( $Si$ ) , germanium ( $Ge$ ) , arsenic ( $As$ ) , and tellurium ( $Te$ ).

· They also form alloys with metals.

· Tin ( $Sn$ ), Aluminium ( $Al$ ), Zinc ( $Zn$ ) are metals.

Correct Option: $C$ .

If A, B and C are the three elements of Dobereiner's triad and atomic weights of A and B are 7 and 15 respectively, then the atomic weight of C is :

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$1$
0%
$11$
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$23$
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$25$

Explanation

According to Dobreiner's triad, the atomic mass of the central element (B) is the arithmetic mean of the atomic masses of the other two elements (A and C ).

Given that:

$A=7,\ B=15$

Let the mass of

$C$ be

$M_C$ .

$M_B = \dfrac{M_A + M_C}{2}$

$15= \dfrac { 7+M_c }{2 }$

$\Rightarrow M_ C=23$ .

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Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
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Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
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Assertion is correct but Reason is incorrect
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Both Assertion and Reason are incorrect

The number of valence electrons ___________ across a period and ________ down the group:

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increases, remains same
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decreases, remains same
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remains same, increases
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increase, decreases

The law used by Newlands to arrange elements is known as Newlands Law of Octaves .

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True
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False

Which of the following can be classified as Dobereiner's triads?

(a) P, As, Sb

(b) Cu, Ag, Au

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a and b
0%
b and c
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a and c
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all of the above

Explanation

$P (31\ u ), As (74.9\ u), Sb (122\ u)$ and (d)

$S(32\ u), Se(79\ u), Te(127.6\ u)$ represent Dobereiners triad.

According to the law of triad proposed by Dobereiners, the atomic weight of a middle element is nearly the same as the average of the atomic weights of the other two elements.

$\displaystyle \frac {31+122}{2} = 76.5 \simeq 74.9 \ u$

$\displaystyle \frac {32+127.6}{2} =79.8 \simeq 79 \ u$

Which of the following has maximum non-metallic character?

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F
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Cl
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Br
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I

According to Mendleev's periodic law which properties of the elements are the periodic function of their atomic masses?

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Physical properties
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Chemical properties
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Physical and chemical properties both
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None of these

On moving from top to bottom in a group in the periodic table, valency:

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increases
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decreases
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remains same
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first increases then decreases

Which of the following pairs of elements does not follow the Law of Octaves?

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$Na, K$
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$Ca, Sr$
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$F, Cl$
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$O, S$

Which of the following is the correct match?
(a) Eka silicon -

$\text{Ge}$
(b) Eka aluminum -

$\text{Ga}$
(c) Eka manganese -

$\text{Tc}$
(d) Eka boron -

$\text{Sc}$

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b, c
0%
a, b, d
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a, d
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All of above

Explanation

Eka is a prefix used to designate the first element of the same family in the periodic table beyond the one to whose name it is prefixed, as Eka manganese

(a) Eka silicon - Ge (germanium)

(b) Eka aluminium - Ga (gallium )

(d) Eka boron – Sc (scandium)

Hence, the correct option is

$\text{D}$

Which of the following pair of elements are expected to have similar properties according to Newland's law of octaves?

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$Ne, Ar$
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$C, N$
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$Na, K$
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$P, S$

Which element has smallest atomic size?

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Fluorine
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Chlorine
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Bromine
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Iodine

Who was the first to classify the elements into metals and non-metals?

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Meyer
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Mendeleev
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Lavoisier
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None of the above

The anomalous pairs in Mendeleev's periodic table is/are_______.

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Co, Ni
0%
Te, I
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Ar, K
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All the above

Explanation

Anomalous pair is a set of two elements in which an element with higher atomic weight is placed before elements with lower atomic weight.

Example:

$Co$ with atomic number 58.93 was placed before

$Ni$ with atomic weight 58.61. Similarly,

$Te$ (127.6 u) was placed before

$I$ (126.9u), and

$Ar$ (39.9u) was placed before

$K$ (39.0).

Thus, all the given options form anomalous pairs.

Which of the following set of elements is written in order of their increasing metallic character?

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$Be< Mg< Ca$
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$Na< Li <K$
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$Mg <Al <Si$
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$C <O< N$

Explanation

The metallic character increases as we move down the group in the modern periodic table. Thus the correct order of metallic character is

$Be<Mg<Ca$ .

Also, the metallic character decreases across the period.

If three elements

$X, Y,$ and

$Z$ form a Dobereiner's triad and atomic weights of

$X$ and

$Z$ are

$9$ and

$40$ respectively, then the atomic weight of the element

$Y$ is approximate:

0%
24.5
0%
49
0%
34.5
0%
29

Explanation

According to Dobereiner, the atomic weight of the central element of the triad is the arithmetic mean of the atomic weights of the other two members.

Therefore, atomic weight of Y =

$\cfrac{9 + 40}{2} = 24.5\ g$

Hence, option A is correct.

The elements

$A$ and

$B$ obey Newland's law of octaves. How many elements are there between

$A$ and

$B$ ?

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7
0%
8
0%
5
0%
6

Explanation

According to the law of octaves, elements with similar physical and chemical properties occur after each interval of seven.

Thus, if

$A$ is the first element and

$B$ is the eighth element, the number of elements in between

$A$ and

$B$ is 6.

Hence, option D is correct.

What type of oxide would Eka-aluminium form?

0%
$EO_3$
0%
$E_3O_2$
0%
$E_2O_3$
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$EO$

Explanation

Eka- Aluminium (E) forms oxide with the same chemical formula as Aluminium oxide. Thus, the formula can be represented as

${ E }_{ 2 }{ O }_{ 3 }$ .

Hence, option C is correct.

The element with the atomic number

$9$ resembles with the element having the atomic number:

0%
$8$
0%
$17$
0%
$36$
0%
$27$

The element in between lithium and potassium according to Dobereiner's classification is:

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Mg
0%
Na
0%
Ca
0%
Rb

Explanation

Dobereiner's law of triads states that 'arithmetic mean of the atomic masses of first and the third element in the triad is approximately equal to the atomic mass of the second element in the triad.

The atomic mass of lithium is

$7$ and Potassium is

$39$ . Their arithmetic mean comes out to be

$\dfrac {7+39}{2}= 23$ , which is the atomic mass of sodium

$(Na)$ .

Hence, the element in between lithium and potassium according to Dobereiner's classification is Na.

According to the Newlands' law of octaves, the properties of fluorine are similar to those of ________ .

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hydrogen
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lithium
0%
sodium
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potassium

Explanation

John Newlands arranged the known elements in increasing order of their atomic masses. He started with the element having the lowest atomic mass ( hydrogen ) and ended at thorium which was the

$56^{th}$ . According to his law, when elements are arranged in order of their increasing atomic masses, the properties of

$8^{th}$ succeeding element resemble with that of the first one. The properties of fluorine are similar to those of hydrogen because fluorine is eight-element starting from hydrogen.

Hence, the correct option is

$A$

The Newland's law of octaves for the classification of elements was found to be applicable only up to the element ______________________.

0%
Potassium
0%
Calcium
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Cobalt
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Phosphorous

Explanation

Newland's law of octaves for the classification of elements was found to be applicable only up to the element

$Calcium$ .

Law of octaves, in chemistry, the generalization made by the English chemist J.A.R. Newlands in 1865 that, if the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties occur after each interval of seven elements.

Newlands was one of the first to detect a periodic pattern in the properties of the elements and anticipated later developments of the periodic law.

The valency of elements in the periodic table with respect to hydrogen:

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increases regularly from $1$ to $8$
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decreases regularly from $1$ to $8$
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first increases from group I to group IV and then decreases
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first decreases from group I to group IV and then increases

Which of the following elements has the maximum number of outermost electrons?

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Na
0%
Mg
0%
Si
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P

Explanation

Sodium has

$1$ electron, magnesium has

$2$ electrons, silicon has

$4$ electrons, and phosphorous has

$5$ electrons in its outermost shell. Therefore, phosphorous has the maximum number of electrons in its outermost shell.

What is the valency of potassium with atomic number

$19$ ?

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$0$
0%
$1$
0%
$2$
0%
$3$

Explanation

The electronic configuration of potassium is

$2,\,8,\,8,\,1$ . The valence shell contains

$1$ electron therefore the valency of potassium is

$1$ .

The element placed with nickel in the table formed by Newlands was :

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iron
0%
cobalt
0%
chromium
0%
copper

Which element resembles cobalt and nickel but was placed in Newlands' table far away from those elements?

0%
Sodium
0%
Calcium
0%
Iron
0%
Chlorine

According to Mendeleev's periodic table, one element whose atomic mass is greater than that of nickel is placed before nickel. Name the element.

0%
Copper
0%
Iron
0%
Zinc
0%
Cobalt

CBSE Questions for Class 10 Chemistry Periodic Classification Of Elements Quiz 4 - MCQExams.com

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Practice Class 10 Chemistry Quiz Questions and Answers

H	Li	Be	B	C	N	O
F	Na	Mg	Al	Si	P	S
Cl	K	Ca	Cr	Ti	Mn	Fe
Co/Ni	Cu	Zn	Y	In	As	Se
Br	Rb	Sr	Ce/La	Zr	-	-

CBSE Questions for Class 10 Chemistry Periodic Classification Of Elements Quiz 4 - MCQExams.com

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Practice Class 10 Chemistry Quiz Questions and Answers

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