Question

Which of the three has the largest ei1? which of the three has the largest ? 1s22s22p63s23p64s1 1s22s22p63s23p5 1s22s22p63s23p1?

Answer 1

`E_i1` will be largest for
`1s^22s^22p^63s^23p^5`.

Step-by-step explanation: Ionization energy is the energy to knock off an electron from a gaseous atom of ion. First ionization energy or
`E_i1` is the energy required to remove 1 loosely held electron from 1 mole of gaseous atoms to produce 1 mole of gaseous ion carrying (+)1 charge.

`M(g)\rightarrow M^+(g)+e^-`

The electrons are filled according to Aufbau's rule and the orbitals which are strongly held to the nucleus follows the order
`s>p>d>f`.

Electron is released from the outermost shell that is from the electrons which are loosely held to the nucleus, this follows the pattern
`s<p<d<f`.

In configurations,
`1s^22s^22p^63s^23p^64s^1,1s^22s^22p^63s^23p^5\text{ and } 1s^22s^22p^63s^23p^1`

The loosely held orbital is 4s, therefore electron will be lost from that easily.

Now, in 3p orbital, one configuration has 5 electrons and one has 1 electron.

The configuration having 5 electrons will be more tightly held by the nucleus because it has more electrons that the one having only 1 electron. Hence, the electron will be lost easily from the configuration having
`3p^1` as the valence shell.

Therefore, the configuration
`1s^22s^22p^63s^23p^5` will the largest
`E_i1`.