Question
Chemistry Question on Classification of elements & periodicity in properties
Correct order of 1st ionisation potential (IP) among following elements Be, B, C, N, O is
B < Be < C < O < N
B < Be < C < N < 0
Be < B < C < N < O
Be < B < C < O < N
B < Be < C < O < N
Solution
The amount of energy required to remove an electron from the outermost orbit of a gaseous atom is known as ionisation potential. Elements having
half-filled or completely filled' orbitals are more stable than partially filled orbitals.
In a period from left to right ionisation potential decreases as the atomic number increases. The given elements (Be, B, C, N, O) are present in II period as
\xrightarrow{\begin {array}
\ Be \ \ \ \ \ \ \ \ B \ \\\
\ Ionisation
\end {array} \begin {array}
\ \ \ C \ \ \ \ \ N \ \ \ \ \ O \\\
\ \ potential \ \ increases \\\
\end {array} }
But in case of Be and B, Be has higher ionisation potential due to stable configuration
So, the correct order of increasing ionisation potential will be
B < Be < C < 0 < N