Question

QUESTION 15 Consider the following electron configurations for neutral atoms: I 1s22522p6352 II - 1522522p63523p4 III-1s22s22p63523p6 Which atom would be expected to have the largest third ionization energy? atom I atom II atom lII All of these atoms would be expected to have the same third ionization energy

Answer 1

ionisation energy is the energy required to remove one electron from an element

electronic configuration of atoms

Atom 1 - 1s² 2s² 2p⁶ 3s²

Atom 2 - 1s² 2s² 2p⁶ 3s² 3p⁴

Atom 3 - 1s² 2s² 2p⁶ 3s² 3p⁶

elements configuration after removal of one electron( after first ionisation energy)

Atom 1 - 1s² 2s² 2p⁶ 3s¹

Atom 2 - 1s² 2s² 2p⁶ 3s² 3p³

Atom 3 - 1s² 2s² 2p⁶ 3s² 3p⁵

elements configuration after removal of one electron( after second ionisation energy)

Atom 1 - 1s² 2s² 2p⁶

Atom 2 - 1s² 2s² 2p⁶ 3s² 3p²

Atom 3 - 1s² 2s² 2p⁶ 3s² 3p⁴

now in Third ionisation energy,

From above configuration,for

Atom 1 - electron will be taken out from a fully filled p orbital

Atom 2- electron will be taken out from a incompletely filled p orbital

Atom 3- electron will be taken out from a incompletely filled p orbital

So,less energy is required to take out electron from partially filled orbitals than a fully filled orbitals as half filled and fully filled orbitals are stable

therefore Atom 1 will have highest third ionisation energy