Tag: electronic configuration and valency

Questions Related to electronic configuration and valency

The element with the highest first ionisation potential is:

  1. Boron

  2. Carbon

  3. Nitrogen

  4. Oxygen


Correct Option: C

The ionisation potential of hydrogen atom is $13.6\ eV$. The energy of required to remove an electrons in the $n=2$ state of hydrogen atom is:

  1. $27.2\ eV$

  2. $13.6\ eV$

  3. $6.8\ eV$

  4. $3.4\ eV$


Correct Option: D
Explanation:
$E _n=-13.6\ ev\left (\dfrac {Z^2}{n^2}\right)=\dfrac {-E _1}{n^2}[I.E _1 =-E _1 =13.6\ eV \Rightarrow E _1=-13.6\ eV]$

$\therefore E _2 =\dfrac {-13.6\ ev}{4}=-3.4ev$

$\therefore I.E _2=-E _2 =3.4\ ev$.

Option D is correct.