Read the following and answer any four questions from 18 (I) to 18 (v).
Metallic Character
Electro positivity also referred to as metallic character, is the capacity of an atom to donate electrons and produce a positive ion (cation). A drop in atomic size over the period causes electro-positivity to increase from left to right, whereas an increase in atomic size causes the metallic character to increase down the group.
Non-Metallic Character
Non-metallic character, also known as electronegativity, is the capacity of an atom to take electrons and produce a negative ion (anion). High electro-negativity elements are more likely to acquire electrons and produce anions. Across the period, from left to right, electronegativity increases due to a decrease in atomic size, while down the group, electronegativity falls due to an increase in atomic size.

(i) The correct order of decreasing metallic character of Alkali metals plotted in the graph is: 

A. $Cs>Rb>Li>Na>K$

B. $K>Rb>Li>Na>Cs$

C. $K>Rb>Li>Na>Cs$

D. $K>Rb>Li>Na>Cs$

(ii) Why is hydrogen is placed along with Alkali metals in the modern periodic table though it shows non-metallic character? 

A. Hydrogen has one electron & readily loses an electron to form a negative ion 

B. Hydrogen can easily lose one electron like alkali metals to form a positive ion 

C. Hydrogen can gain one electron easily like Halogens to form a negative ion 

D. Hydrogen shows the properties of non-metals  

(iii) Among the following the highest electronegative element is

A. F

B. Cl

C. Br

D. I

(iv) The gradual change is electronegativity down the group for halogens is due to: 

A. Electronegativity increases down the group due to decrease in atomic size. 

B. Electronegativity decreases down the group due to a decrease in the tendency to lose electrons.  

C. Electronegativity decreases down the group due to an increase in atomic radius/ tendency to gain electron decreases.  

D. Electronegativity increases down the group due to an increase in forces of attraction between the nucleus an valence electrons. 

 

(i) 

Alkali metals include sodium$Na$, potassium$K$, lithium$Li$, cesium$Cs$, and rubidium$Rb$.
On the periodic table, they belong to group 2.
As we proceed from top to bottom in the alkali metal group, the size of the metals increases due to the addition of valence shells, and their metallic nature also increases.

Therefore, $Cs>Rb>K>Na>Li$is the proper sequence of the metallic nature of the Alkali metals represented in the graph

Hence, the correct option is c) $Cs>Rb>K>Na>Li$

 (ii) 

Hydrogen is placed along with Alkali metals in the modern periodic table though it shows the non-metallic character as Hydrogen can easily lose one electron like alkali metals to form a positive ion.
Hydrogen occupies a place in the periodic table as a non-metal with the same $n{s}^1$electron configuration as alkali metals. But it creates cations much$\left(H^{+}\right)$much more reluctantly than the other alkali metals, which is a significant difference. 

Hydrogen doesn’t form a negative ion, and hence the other options are incorrect. Hence, the correct option is b) as Hydrogen can easily lose one electron like alkali metals to form a positive ion.

(iii) 

The ability of an atom or functional group to accept electrons or attract an electron from other atoms or functional groups is known as electronegativity. 

According to the periodic table, the atoms that make up the Halogen group (Group 17) are 

Fluorine (𝐹), Chlorine (𝐶𝑙), Bromine (𝐵𝑟), Iodine (𝐵𝑟), and Astatine (𝐴𝑡). 

Because they only require one additional electron to complete their octet, halogen atoms have the highest electronegativity because of their stronger attraction to electrons. 

The electronegativity of the atoms in the halogen group is as follows: 

Astatine (𝐴𝑡): 2. 2 

Fluorine (𝐹): 4. 0 

Chlorine (𝐶𝑙): 3. 0 

Bromine (𝐵𝑟): 2. 8 

Iodine (𝐼): 2. 5

Therefore, based on the above table, we may infer that the electronegativity of halogens is as follows:

$F>Cl>Br>I>At$

Hence the correct option is a) F

(iv) 

The ability of an atom or functional group to accept electrons or attract an electron from other atoms or functional groups is known as electronegativity.
According to the periodic table, the atoms that make up the Halogen group (Group 17) are Fluorine F, Chlorine Cl, Bromine Br, Iodine I, and Astatine At
Because they only require one additional electron to complete their octet, halogen atoms have the highest electronegativity because of their stronger attraction to electrons.

Therefore, electronegativity decreases down the group due to increase in atomic radius/ tendency to gain electron decreases. Hence the correct option is c) Electronegativity decreases down the group due to increase in atomic radius/ tendency to gain electron decreases.

(v) Fluorine (72 pm) has a smaller atomic radius than Lithium (152 pm). F and Li are in the same period, and across the period, atomic size/radius decreases from left to right. Due to the increase in effective nuclear charge, the atomic radius decreases from left to right. Options a), b), and c) are not the correct explanation for the given statement.
Hence, the correct option is d) F and Li are in the same period, and across the period, atomic size/radius decreases from left to right.