Question

The chemical symbol for nitrogen gas is
     (A) $Ni$
     (B) ${{N}_{2}}$
     (C) ${{N}^{+}}$
     (D) $N$

Answer 1

Hint: Nitrogen gas is a diatomic molecule which is composed of two nitrogen atoms. Nitrogen gas exists as dinitrogen. So, we must look for the diatomic molecule in the given options

Complete step by step solution:
     - As everybody knows nitrogen is a chemical element with atomic number seven in the group fifteen of the periodic table. Nitrogen is a p block element. It was discovered by a Scottish physician Daniel Rutherford in the year 1772.
     - Nitrogen is a common element in the universe with approximately seventh in total abundance in the milky way and solar system.
    -Nitrogen comprises about 78$%$ of earth's atmosphere and hence it is the most abundant uncombined element. The nitrogen on earth is cycled naturally by living organisms through a cycle called nitrogen cycle.
    - Atomic nitrogen is highly reactive being a tri radical with three unpaired electrons.
    - Elemental nitrogen usually occurs as molecular dinitrogen (${{N}_{2}}$). It’s an odourless, tasteless and colorless diamagnetic gas at standard conditions.
    - Nitrogen gas or dinitrogen is usually unreactive at room temperature. As we know this is due to the triple bond among diatomic nitrogen ($N\equiv N$).
    - Dinitrogen must have a triple bond to follow the octet rule. As we know, nitrogen has a total of five valence electrons. Hence doubling that we would have a total of ten valence electrons with dinitrogen. As a total of eight electrons is required to have a full valence shell in an atom, here in the case of nitrogen it needs to have a triple bond.
 - Since triple bonds are very hard to break, this nitrogen gas is usually inert.

The answer is option (B). The chemical symbol for nitrogen gas can be written as ${{N}_{2}}$.


Note: Since the given options appear similar to each other, there may be a chance of confusion. $Ni$is the symbol for nickel , $N$represents the elemental nitrogen and ${{N}^{+}}$ represents the nitrogen ion which is formed from the loss of an electron. ( $N\to {{N}^{+}}+{{e}^{-}}$ )