Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar?

Question

Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar? (A) Ca < Ba < S < Se < Ar (B) S < Se < Ca < Ba < Ar (C) Ba < Ca < Se < S < Ar (D) Ca < S < Ba < Se < Ar

Tardigrade Admin · Accepted Answer

On moving left to right ionization energy increases as size decreases and on moving top to bottom in a group, size increases. So ionization energy decreases.
Hence, order of increasing first ionization enthalpy i.e.,

Δ H_{I E_{1}}

is Ba < Ca < Se < S < Ar

Q. Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar?

Ca < Ba < S < Se < Ar

S < Se < Ca < Ba < Ar

Ba < Ca < Se < S < Ar

Ca < S < Ba < Se < Ar

On moving left to right ionization energy increases as size decreases and on moving top to bottom in a group, size increases. So ionization energy decreases. Hence, order of increasing first ionization enthalpy i.e., ΔHIE1​​ is Ba < Ca < Se < S < Ar

On moving left to right ionization energy increases as size decreases and on moving top to bottom in a group, size increases. So ionization energy decreases.
Hence, order of increasing first ionization enthalpy i.e., $Δ H_{I E_{1}}$ is Ba < Ca < Se < S < Ar