Question

PART A:
Arrange the elements in decreasing order of first ionization energy.
Rank from highest to lowest first ionization energy. To rank items as equivalent, overlap them.

In, Ge, Se, Cs

PART B:
Arrange the elements in order of decreasing first ionization energy. Rank from highest to lowest first ionization energy. To rank items as equivalent, overlap them.

element x (radius (pm): 110)
element y (radius (pm): 199)
element z (radius (pm): 257)

Answer 1

Concepts and reason

Ionization energy:

It is the energy required to remove an electron from a neutral atom in the gaseous phase. First ionization energy:

First ionization energy is also called initial ionization energy, \(\mathrm{E}_{\mathrm{i}}\) of an atom or molecule is the energy required to remove one mole of an electron from one mole of isolated gaseous atoms or ions.

Fundamentals

lonization energy and the periodic table:

1.From left to right, the valance shell stability increases, and hence, the ionization energy of the elements increases. Noble gases have high ionization energy as their valance shells are fully occupied.

2.From top to bottom, the electron shielding effect increases, and hence, the ionization energy of the elements decrease. As the size increases, ionization energy decreases.

 

Part A 

The decreasing order of ionization energy is as follows:

\(\mathrm{Se}>\mathrm{Ge}>\operatorname{In}>\mathrm{Cs}\)

Part A The decreasing order of ionization energy of the elements is as follows:

\(\mathrm{Se}>\mathrm{Ge}>\operatorname{In}>\mathrm{Cs}\)

Ge and Sebelong to 4th period, Inbelongs to 5th period, and Csbelongs to 6th period. Down the period, ionization energy decreases. Hence, Ge and \(\mathrm{Se}>\mathrm{In}>\mathrm{Cs}\) Gebelongs to group-14 and Sebelongs to group-16. Across the group, ionization energy increases. Hence, Se \(>\) Ge.

 

Part B

The decreasing order of ionization energy is as follows:

\(\mathrm{X}>\mathrm{Y}>\mathrm{Z}\)

Part B The decreasing order of ionization energy of the elements is as follows:

\(\mathrm{X}>\mathrm{Y}>\mathrm{Z}\)

As the atomic radius increases, ionization energy decreases due to the shielding effect. The radius of Xis 110pm, the radius of \(Y\) is 199 pm, and the radius of \(Z\) is 257 pm. Hence, the order is \(X>Y>Z\).