MCQ Questions for Class 10 Chemistry Periodic Classification Of Elements Quiz 3

The total number of inert gases among the following is:

H, He, Ne, F, Ar, Kr, K

0%
1
0%
2
0%
3
0%
4

Arrange the following elements in the order of their decreasing metallic character.

N a, S i, C l, M g, A l

$Na,\ Si,\ Cl,\ Mg,\ Al$

0%
$Cl > Si >Al > Mg >Na$
0%
$Na >Mg >Al >Si > Cl$
0%
$Na > Al > Mg > Cl > Si$
0%
$Al > Na> Si > Ca> Mg$

Explanation

Metallic character depends upon the ability to lose electrons. Metallic character decreases, on moving from left to right in a period because the force of attraction between the nucleus and the outermost electron increases thereby the atomic size decreases. Therefore, it becomes difficult for the metal to lose electrons from the outermost shell.

Therefore, the order is

N a > M g > A l > S i > C l

$Na>Mg>Al>Si>Cl$ .

Mendeleev predicted the existence of certain elements not known at that time and named as Eka-aluminiumT he elements which have taken the place of Eka-aluminium is :

0%
Germanium
0%
Gallium
0%
Silicon
0%
Aluminium

Explanation

Eka-silicon means germanium. It occurred because of silicon whereas eka-aluminium occurred because of aluminium and later named it gallium.

While filling the elements considering atomic number would be main and fundamental property there were gaps in the mentioned groups hence he filled them with these names.

Hence the correct option is

B

$B$ .

Which among the following elements has the largest atomic radii?

0%
$Na$
0%
$Mg$
0%
$K$
0%
$Ca$

Explanation

The atomic radii increase down the group and decrease across a period.

Among the given options, the atomic radii will increase in the following order:

M g < N a < C a < K

$Mg<Na<Ca<K$ .

The period of element with atomic number 20 in the periodic table is:

0%
1
0%
2
0%
3
0%
4

The group number of element with atomic number 7 in the periodic table is:

0%
2
0%
18
0%
15
0%
14

Explanation

Atomic no.

7

$7$ is Nitrogen which is in group

15.

$15.$

Which group of elements could be placed in Mendeleev's Periodic Table without disturbing the original order?

0%
Alkali metals
0%
Alkaline earth metals
0%
Non - metals
0%
Noble gases

The three elements A, B and C with similar properties have atomic masses X, Y and Z respectively. The mass of Y is approximately equal to the average mass of X and Z. Such an arrangement of elements called as :

0%
Dobereiner triad
0%
Mendeleev triad
0%
Newland triad
0%
None of the above.

Explanation

Dobereiner observed in a few atoms that the mass of one atom is equal to the average of two atoms. He defined almost all properties based on atomic weight. Hence, this is called Dobereiner triad.

Lithium has 7, sodium has 23 whereas potassium has 39 as atomic masses.

23 = (7 + 39) / 2 = 23

$23 = (7+39)/2 = 23$

Here, we could observe that atomic mass of sodium is the average of atomic masses of potassium and lithium.

Dobereiner grouped the elements into triads and Newland gave the:

0%
Law of Octaves
0%
Law of multiple proportion
0%
Law of constant proportion
0%
None of these

Which of the following is not a noble gas?

0%
Helium
0%
Xenon
0%
Radium
0%
Radon

Statement: In Dobernier's classification of elements, the atomic mass of the middle element is equal to the average atomic masses of the extreme elements of a triad.

State whether the given statement is true or false.

0%
True
0%
False

Explanation

Dobereiner classified the elements into triads (group of three). He made the groups such that the atomic mass of the middle element was the average atomic mass of the other two elements. This is Dobernier's law of triads.

L i

$Li$ ,

N a

$Na$ ,

K

$K$ is an example of Dobereiner's triad. Here, the average atomic mass of

L i

$Li$ and

K

$K$ is equal to the atomic mass of

N a

$Na$

\frac{(7 + 39)}{2} = 23

$\frac{(7+39)}{2} = 23$

Thus, given statement is true.

The number of valence electrons of caesium is:

0%
1
0%
2
0%
6
0%
3

If the two members of a Dobereiner's triad are chlorine and iodine, then the third member of this triad is :

0%
fluorine
0%
bromine
0%
sodium
0%
calcium

Explanation

According to Dobereiner, the atomic mass of the middle element is nearly equal to the arithmetic mean of the other two.

Therefore, the atomic mass of the third element is

=

$=$

\frac{35.5 + 127}{2}

$\dfrac{{35.5}+{127}}{2}$

=

$=$ 81.25, which is the atomic mass of bromine.

Which of the following triads does not follow Dobereiner's law of triads?

0%
Li, Na, K
0%
Ca, Sr, Ba
0%
Be, Mg, Ca
0%
Cu, Ag, Au

Which of the following elements has the least non-metallic character?

0%
Fluorine
0%
Chlorine
0%
Bromine
0%
Iodine

Mendeleev classified elements in:

0%
increasing order of atomic groups.
0%
seven periods and eight groups.
0%
seven periods and nine groups
0%
eight periods and seven groups.

Explanation

Mendeleev kept elements in increasing order of atomic weights in seven periods and eight groups.
Therefore, option

B

$B$ is correct.

Atomic number of an element isWhat is the nature of the element?

0%
Alkali metal
0%
Transition metal
0%
Non metal
0%
Halogen

Explanation

Atomic number 16 have

2, 8, 6

$2,8,6$ configuration and so to complete octet it needs two electron thus has tendency to accept electron.
Due to this electron accepting tendency, it is non-metal.

Which has more non-metallic character from the elements

$' X'$ and

$' Y'$ , with electronic configurations

$2, 8, 5$ and

$2, 8, 6$ respectively?

0%
$X$
0%
$Y$
0%
Both have same non-metallic character
0%
None of the above

Explanation

As we move from left to right across a period, the non-metallic character increases. Here,

$X$ has atomic number

$15$ , so, the element is Phosphorous.

$Y$ has atomic number

$16$ , so, the element is Sulphur. As sulphur is present more to the right of the table, so according to the general trend it is more non-metallic. So,

$Y$ has more non-metallic character.

Hence, option

$B$ is correct.

Name the following with reference to the elements of the modern periodic table.

The alkali metal in period 2

0%
H
0%
Li
0%
Rb
0%
Cs

The element with maximum non metallic character is:

0%
$S$
0%
$P$
0%
$Cl$
0%
$Ag$

Explanation

As we move down the group, tendency to lose electron increases and metallic character increases while as we move across a period, electronegativity increases so non-metallic character increases.

So, among these

$Cl$ have highest non-metallic character.

Hence, option C is correct.

The type of elements present in group 18[0] are :

0%
alkali metals
0%
alkaline earth metals
0%
halogens
0%
noble gases

$K$ has a larger atomic radius than

$Li$ . This confirms:

0%
atomic radius decreases down a group.
0%
atomic radius increases down a group.
0%
atomic radius decreases across a period.
0%
atomic radius increases across a period.

Explanation

Atomic radius increases down a group.

$K$ and

$Li$ are in the same group, and

$K$ lies below

$Li$ .

$K$ has a larger atomic radius than

$Li$ . This happens because as we move down the group new shells are added and this increases the distance between the outermost electron and the nucleus.

Atomic weight of which set of elements were corrected by Mendeleev?

0%
$Li, Na, K$
0%
$U, Be, In$
0%
$Tc, Sc, Al$
0%
None of the these

Explanation

Mendeleev corrected atomic weights of Uranium, Beryllium, and Indium (

$U, Be, In$ ) based on their positions in the periodic table. Along with that he also corrected the atomic weights of Gold (

$Au$ ) and Platinum (

$Pt$ ).

Options

$B$ is correct.

Which is not anomalous pair of elements in the Mendeleev's periodic table?

0%
$Ar$ and $K$
0%
$Co$ and $Ni$
0%
$Te$ and $I$
0%
$Al$ and $Si$

Explanation

Anomalous pairs are those pairs of elements in which the increasing order of atomic masses was not obeyed. Mendeleev placed these elements according to a similarity in properties and not in the increasing order of their atomic mass.
(A)

$Ar$ ( at mass = 39.9) is placed before

$K$ (at mass = 39.1)
(B)

$Co$ (at mass = 58.9) is placed before

$Ni$ (at mass = 58.6)
(C)

$Te$ (at mass = 127.6 ) is placed before

$I$ (at mass = 126.9).
(D)

$Al$ and

$Si$ is not anomalous pair of elements in the Mendeleev's periodic table.

$Al$ (at mass = 26.98) is placed before

$Si$ (at mass = 28.4) means

$Al$ and

$Si$ are in increasing order of their atomic masses. Therefore they are not Anomalous pair.

The type of elements present in group 17 [VIIA] are :

0%
alkali metals
0%
alkaline earth metals
0%
noble gases
0%
halogens

The term atomic radius refers to?

0%
Charge of the atom
0%
Size of the atom
0%
Distance between the centre of nucleus and the first shell
0%
Size of the outermost orbital

In which part of a group would you separately expect the elements to have the greatest metallic character?

0%
group 1
0%
group 2
0%
group 17
0%
group 18

Fill in the blanks with the appropriate words in each case

Element 'B' in period 2 is to the right of element 'A'.
Element 'B' is likely to be ____non-metallic in character than element 'A'

0%
more
0%
less
0%
same
0%
none of these

In the periodic table, the metallic character of element :

0%
decreases from left to right across a period and on descending a group
0%
decreases from left to right across a period and increases on descending a group
0%
increases from left to tight across a period and on descending a group
0%
increases from left to right across a period and decreases on descending a group

The diagram represents an atom 'X'. Answer the following.

If atom 'X' has 1 electron in its outer shell, is it a non-metal.

0%
True
0%
False

CBSE Questions for Class 10 Chemistry Periodic Classification Of Elements Quiz 3 - MCQExams.com

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Practice Class 10 Chemistry Quiz Questions and Answers

CBSE Questions for Class 10 Chemistry Periodic Classification Of Elements Quiz 3 - MCQExams.com

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Practice Class 10 Chemistry Quiz Questions and Answers

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