Which has lowest and highest first ionisation enthalpy in 3d series?a)Sc and Znb)Zn and Scc)Cu and Znd)Cr and ZnCorrect answer is option 'A'. Can you explain this answer?

Question

Answer

Losing one electron gives Sc noble gas configuration (Ar). While Zn has d10 s2 configuration so it won't give its electron easily. So, it has high ionization enthalpy.

Answer

Sc (3d¹4s²)has 631 kJ mol^-1 and Zn (3d¹⁰ 4s²) has 906 kJ mol^-1

Answer

Lowest and Highest First Ionisation Enthalpy in 3d Series

To determine the lowest and highest first ionisation enthalpy in the 3d series, we need to look at the trends in ionisation enthalpy across the series.

Trends in Ionisation Enthalpy
The first ionisation enthalpy is the energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous ions with a single positive charge. It is influenced by several factors, including effective nuclear charge, atomic radius, and electron-electron repulsion.

Lowest First Ionisation Enthalpy
The first ionisation enthalpy generally decreases across a period from left to right due to the increasing effective nuclear charge. However, there are exceptions when there is a half-filled or fully filled subshell, which results in increased stability and higher ionisation enthalpy.

In the 3d series, the element with the lowest first ionisation enthalpy is Scandium (Sc). Scandium has an electron configuration of [Ar] 3d1 4s2. It has a single electron in the 3d orbital, which is relatively easy to remove due to its location farther from the nucleus compared to the 4s electrons. Therefore, Scandium has the lowest first ionisation enthalpy in the 3d series.

Highest First Ionisation Enthalpy
The first ionisation enthalpy generally increases down a group due to the increasing atomic radius and decreasing effective nuclear charge. The trend is not affected by the half-filled or fully filled subshell.

In the 3d series, the element with the highest first ionisation enthalpy is Zinc (Zn). Zinc has a completely filled 3d orbital with an electron configuration of [Ar] 3d10 4s2. The 3d10 electrons are tightly held by the nucleus, making it more difficult to remove an electron from Zinc compared to other elements in the series. Therefore, Zinc has the highest first ionisation enthalpy in the 3d series.

Conclusion
In summary, Scandium (Sc) has the lowest first ionisation enthalpy in the 3d series due to the relatively easy removal of its 3d electron. Zinc (Zn) has the highest first ionisation enthalpy in the 3d series due to the tightly held 3d10 electrons in its completely filled orbital.

Top Courses for Class 12View all

English Class 12

Chemistry Class 12

Physics Class 12

English Flamingo Class 12

Physical Education Class 12(XII) - Notes & Model Test Papers

Top Courses for Class 12

Top Courses for Class 12

Related Content

Schools

Competitive Examinations

Quick Access Links

Technical Exams