Question

The element with atomic number 9 resembles in properties with the element having atomic number:
(A) 19
(B) 17
(C) 36
(D) 27

Answer 1

The element with atomic number 9 is fluorine and is a halogen. It will show properties similar to another halogen atom only. It belongs to group 17 and this group is known as halogen group.

Complete step by step answer:
-First of all we will see which element belongs to atomic number 9.
The atomic number 9 belongs to fluorine, which is a halogen. Its atomic mass is 19 g/mol. Its electronic configuration is: $1{s^2}2{s^2}2{p^5}$. This element belongs to group 17 and period 2 period and the group 17 is known as halogen group. It is the lightest halogen atom and exists as a highly toxic pale yellow diatomic gas. Also fluorine is the most electronegative element and is extremely reactive. It reacts with all elements except the noble gases (Ar, Ne and He).

-Now let us take a look at all the elements belonging to group 17 and their atomic numbers.
Group 17 contains 5 elements. They are: fluorine (atomic number = 9), chlorine (atomic number = 17), bromine (atomic number = 35), iodine (atomic number = 53) and astatine (atomic number = 85).
-The halogens are salt producing elements. They have the ability to produce a wide range of salts by reacting the halogens with metals. They produce salts like sodium chloride (NaCl), calcium fluoride (CaF), silver bromide (AgBr), etc.

-Now we will look at the options and check whether or not they belong to the halogen group.
For (A) 19: Atomic number 19 belongs to potassium (K) which is an alkali metal not any halogen.
For (B) 17: Atomic number 17 belongs to chlorine (Cl) which is a halogen and so it will share properties similar to that of fluorine.
For (C) 36: Atomic number 36 belongs to krypton (Kr) which is a noble gas not a halogen.
For (D) 27: Atomic number 27 belongs to cobalt (Co) which is a transition metal not a halogen.
From the above discussion we can say that the element with atomic number 9 (Fluorine) will show properties similar to the element with atomic number 17 (chlorine) because both are halogens.
So, the correct answer is “Option B”.

Note: The general electronic configuration of the halogens is: $n{s^2}n{p^5}$. Group 17 is the only group in which elements of all states of matter are present. For example: fluorine and chlorine are gases, bromine is liquid and iodine is solid. All the halogens are great oxidizing agents and fluorine is the most powerful oxidizing agent.