Chemistry
Class 11th Federal board
Topic:Ionization Energy
The minimum energy required to remove outermost electron from(most losely bounded
electron)from an gaseous ion atom.
Trends:
Ionization energy across group:
The ionization energy decreases across group because;
⦁ The shielding effect increases across group.
⦁ The atomic radius increases.
⦁ The attraction between nucleus and shells decreases.
⦁ The less energy required to remove electron.
Ionization energy across period:
The ionization energy across period increases because;
⦁ The shielding effect remain constant.
⦁ The atomic radius remain constant.
⦁ The nuclear charge increases.
⦁ Attraction between nucleus and shells increases.
Factors affecting ionization energy:
There are many factors which affect the ionization energy;
⦁ the nuclear charge of atom is directly proportional to ionization energy.
⦁ the shielding effect of atom is inversely proportional to ionization energy.
⦁ the atomic radius of atom is inversely proportional to ionization energy.
⦁ the ionization energy may vary by their positions in periodic table,like the
atoms present on the right side of periodic table have high ionization energy and
the atoms present on left side of periodic table have low ionization energy.
Some extra points:
⦁ the atoms with high ionization energy are called non-metals.
⦁ the atoms with low ionization energy are called metals.
⦁ the atoms with intermediate ionization energy are called metalloids.
Electronic configuration filling:
⦁ some atoms are completely filled like neon 1s2,2s2,2p6.
⦁ some atoms are half filled like 1s2,2s2,2p3.
⦁ some atoms are partially filled like 1s2,2s2,2px2,2py2,2pz1.
Abnormal behaivour of atoms in periodic table:
As we learnt that ionization energy increases across period so some elements in
period show some abnormal behaivour like Be4 and B5,these atoms lie in same period
but Be will have more ionization energy because it is completely filled electronic
configuration.
Class 11th Federal board
Topic:Ionization Energy
The minimum energy required to remove outermost electron from(most losely bounded
electron)from an gaseous ion atom.
Trends:
Ionization energy across group:
The ionization energy decreases across group because;
⦁ The shielding effect increases across group.
⦁ The atomic radius increases.
⦁ The attraction between nucleus and shells decreases.
⦁ The less energy required to remove electron.
Ionization energy across period:
The ionization energy across period increases because;
⦁ The shielding effect remain constant.
⦁ The atomic radius remain constant.
⦁ The nuclear charge increases.
⦁ Attraction between nucleus and shells increases.
Factors affecting ionization energy:
There are many factors which affect the ionization energy;
⦁ the nuclear charge of atom is directly proportional to ionization energy.
⦁ the shielding effect of atom is inversely proportional to ionization energy.
⦁ the atomic radius of atom is inversely proportional to ionization energy.
⦁ the ionization energy may vary by their positions in periodic table,like the
atoms present on the right side of periodic table have high ionization energy and
the atoms present on left side of periodic table have low ionization energy.
Some extra points:
⦁ the atoms with high ionization energy are called non-metals.
⦁ the atoms with low ionization energy are called metals.
⦁ the atoms with intermediate ionization energy are called metalloids.
Electronic configuration filling:
⦁ some atoms are completely filled like neon 1s2,2s2,2p6.
⦁ some atoms are half filled like 1s2,2s2,2p3.
⦁ some atoms are partially filled like 1s2,2s2,2px2,2py2,2pz1.
Abnormal behaivour of atoms in periodic table:
As we learnt that ionization energy increases across period so some elements in
period show some abnormal behaivour like Be4 and B5,these atoms lie in same period
but Be will have more ionization energy because it is completely filled electronic
configuration.
