Ionization-energy-definition-group-13-elements-inert-gas-isotopes

What is Ionization energy or ionization enthalpy?

Ionization energy or first ionization energy is defined as the minimum amount of energy required to remove the most loosely bound electron of an isolated neutral gaseous atom, converting into ion with one unit positive charge.

                             M (g)           +         I.E               ⟶            M⁺(g)       +      e-

          (Isolated gaseous atom)   Ionization energy     (Gaseous ion)

Units of ionization enthalpy: Since ionization enthalpy is related with energy, hence the unit of ionization potential should the same of energy.

Ionization energy has three types of unit, namely electron volt/atom (eV/atom), kcal/mol, kJ/mol.

 Why does the order of ionization energy value of group-13 elements not regular?

Generally, the order of ionization energy decreases when we move from top to button along a group.

But, in case of group-13 elements, the order of ionization enthalpy change is not regular. It has been found that the value of ionization energy from B to Al decreases.

This is because in this case the combined effect of increasing the size of the atom and the screening effect exceeds the effective nuclear charge of the atom.

On the other side, the value of ionization energy from Al to Ga slightly (2 kJ/mole) increases.

This is because Ga-atom has 3d-electrons. Now 3d-orbital shows weak shielding effect.

Hence 3d-electrons are unable to shield the outer most valence electrons properly. Consequently, the effective nuclear charge of Ga is slightly higher than Al.

Again, the value of ionization potential decreases from Ga to In. In case of In, the screening effect of inner atomic orbital are more effective than effective nuclear charges.  

Hence the effective nuclear charge for outer most electrons is than expected. So the value of ionization energy of ‘In’ is less than Ga.

Finally, the value of ionization enthalpy increases from In to Tl. That is, the value of ionization enthalpy of Tl is higher than In.

In this case, the effective nuclear charge of Tl atom is more effective than In atom due to weak shielding effect of 4f and 5d electrons of Tl-atom.

Therefore, the value of ionization energy of Tl-atom is greater than that of In-atom.

Why is the value of ionization energy of inert gases higher?

 

The outer electronic configuration of inert gas elements are ns2 np6. That is, each inert gas element occupied eight electrons (octet) in their outer most shell.

Besides, all the inner orbital of inert gas elements are completely filled by electrons. Such type of electronic configuration becomes more stable electronic configuration.

Therefore, a large amount of energy is required to convert an inert gas into an ion by removing an electron from the outer most shell. As a result, the value of ionization energy of inert gas element higher.

 

Are the values ​​of the first I.E of two isotopes of the same element equal or different?

 

Ionization energy of atom or molecule depends on few factors such as, atomic size, effective nuclear charge, outer electronic configuration, shielding effect, penetrating power of orbital and half filled or full filled orbital.

 

Now, in case of two isotopes of the same element, the number electrons and their electronic configuration are equal. Again, their nuclear charge and atomic radius are also identical.

 

Consequently the values ​​of the first ionization energy of two isotopes of the same element should be equal.

 

 

 

• What is Ionization energy or ionization enthalpy or ionization potential?
• Why is the value of ionization energy of inert gases higher?
• Are the values ​​of the first I.E of two isotopes of the same element equal or different?
• Why is the ionization potential of Na+ higher than Ne?
• Why is the ionization enthalpy of Na+ higher than Na?
• Why is the ionization potential of nitrogen higher than oxygen?
• Why is the ionization energy of inert gases higher?
• Why is the ionization potential of phosphorous higher than sulfur?
• Why is the I.P of Cu higher than that of K, even though both have 4s1 electrons in their outer orbital?

 

Ionization energy definition, ionization energy of group-13 elements, ionization energy of isotopes, ionization energy of inert gas elements.