Question

What is the symbol for an element in noble gas?
A) $F$, $Cl$, $Br$, $I$
B) $Be$, $Mg$, $Ca$, $Sr$
C) $He$, $Ne$, $Ar$, $Kr$
D) None of these

Answer 1

Hint: We have to know that the halogen family is group $17$, Noble gas family is group $18$ and Alkaline Earth metals belong to group $2$. Noble gas has stable electronic configuration as the octet for the elements present in this group is completely filled.

Complete answer:
Before solving this question, we must look at certain properties of noble gases and their position in the periodic table.
We have to remember that the noble gases were initially said to be rare or inert since they have certain properties in them. Lately they were termed as Noble gas.
It belongs to group $18$,
Noble gases have stable electronic configuration since electrons are completely filled in the orbitals.
For example we can look at electronic Configuration of \[Ne:1{s^2}2{s^2}2{p^6}\]
Option A) this is an incorrect option, since these elements $F$, $Cl$, $Br$, $I$ belongs to group $17$ i.e. Halogen family.
They have only one electron left to complete its octet or you can say to attain noble gas stability.
For an instance look at the electronic configuration of \[F:1{s^2}2{s^2}2{p^5}\]
Option B) this is an incorrect option, since these elements $Be$, $Mg$, $Ca$, $Sr$ belongs to group $2$ i.e. Alkaline earth metals.
We can look at this example, Electronic configuration of \[Be:1{s^2}2{s^2}\]
Option C) this is a correct option, since $He$, $Ne$, $Ar$, $Kr$ these elements belong to the Noble gas class.
As we have discussed above about the properties of noble gas.
Thus we can say that these elements belong to noble gas.
Option D) this is an incorrect option

So,the correct answer is option C.

Note:
We have to know that one must look at the periodic table to know the positions of the elements present. Noble gas elements can sometimes show the properties of inert material that’s why they can be termed as Rare or Inert elements too.