Name the following element: A monovalent non-metal present in fluorspar.

Fluorspar has a chemical formula CaF 2 that is the main source of fluorine. It is used in the nonstick coating of pans. Fluorine is a non-metal that is present in fluorspar and has valency 1 . Fluorine belongs to group 17 .

Observe the given table and answer the following question: Elements A B C D E Atomic number 11 4 2 7 19 Identify the two elements that belong to the same period and the two elements that belong to the same group. Give a reason for your conclusion.

From the given table, elements A and E ate belongs to the same group because in both last shells i.e. outermost shell the valency is one; therefore it belongs to the same group. And elements D and B belong to the same period because both have the same shell and i.e, two.

The position of elements A, B, and C in the Periodic Table are shown below. Group 16 Group 17 - - - - - A B C State whether C is more reactive or less reactive than A.

C is less reactive than A. This is due to the fact that atomic radius increases in size with an increase of electronic energy levels. This lessens the attraction for valence electrons of other atoms, decreasing reactivity. This decrease also occurs because electronegativity decreases down a group; therefore, there is less electron "pulling."

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Earn 100

Read carefully the following statements regarding the ions ${Na}^{+}, {Mg}^{2 +}, F^{-} and O^{2 -}$ .

(I) All ions have the same number of valence electrons.
(II) All ions belong to the elements of the same period of the periodic table.
(III) All ions have the same electronic configuration.
(IV) All ions have the same number of electron shells.

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Important Questions on Periodic Classification of Elements

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

An atom has electronic configuration

2, 8, 7

. To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses)

MEDIUM

Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

An element X has an electronic configuration of

2, 8, 8, 2

belongs to the period _____.

HARD

Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

How the valency and size of atom of an element change when you move from top to bottom in group and left to right in period in modern periodic table?

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

An element P belongs to the

4

th period and group

17

of the long form of the periodic table. Name the element.

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

What do you mean by period and group in the periodic table?

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

An element P belongs to the

4

th period and group

17

of the long form of the periodic table. Write the formula of its compound, when it reacts with element Q having valency

3 +

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

The atomic number of a few elements are

10, 27, 7, 14 .

Identify the elements.

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

How are the limitations Mendeleev's periodic table rectified in the modern periodic table?

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

Write the merits of the modern periodic table over Mendeleev's Periodic table.

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

Which element has twice as many electrons in its second shell as in its first shell?

HARD

Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

An element P belongs to the

4

th period and group

17

of the long form of the periodic table. How many valence electrons are there in element P?

EASY

Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass.

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

An element P belongs to the

4

th period and group

17

of the long form of the periodic table. What is the valency of P?

HARD

Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

Name the following element:

A monovalent non-metal present in fluorspar.

HARD

Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

Observe the given table and answer the following question:

Elements	A	B	C	D	E
Atomic number	$11$	$4$	$2$	$7$	$19$

Identify the two elements that belong to the same period and the two elements that belong to the same group. Give a reason for your conclusion.

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

Do as directed:

In the Modern Periodic Table I am an element belonging to the second group and third period. Who am I?

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

The atomic numbers of elements A, B, C and D are

3, 9, 4

and

8

respectively. Elements having metallic nature amongst these are _____.

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Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

The position of elements A, B, and C in the Periodic Table are shown below.

Group 16	Group 17
-	-
-	-
-	A
B	C

State whether C is more reactive or less reactive than A.

HARD

Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

The electrons in the atoms of four elements A, B, C and D are distributed in three shells having

1, 3, 5

and

7

, electrons respectively in their outermost shells. Write the group numbers in which these elements are placed in the Modern Periodic Table. Write the electronic configuration of the atoms of B and D, and the molecular formula of the compound formed when B and D combine.

HARD

Science>Chemistry>Periodic Classification of Elements>The Modern Periodic Table

Five elements

A, B, C, D

and

E

have atomic numbers of

2, 3, 7,10

and

18

respectively. The elements which belong to the same period of the periodic table are:

Important Questions on Periodic Classification of Elements

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