State whether ionization energy increases and decreases on going down a group of the periodic table.
State whether ionization energy increases and decreases on going down a group of the periodic table.
Step-1: Introduction
The ionization energy is the energy needed to separate an electron from the outer shell of isolated atom. It is denoted as IE. The atomic size, effective nuclear charge and screening effect are the factors that influence the ionization energy.
Step-2: Trend of ionization energy
The ionization energy enlarges on moving from left to right across the period due to the decrease in size of atom on increasing the atomic number and thus, the electrons in valence shell goes nearer to the nucleus. There is more energy needed to separate an electron from outermost shell.
The ionization energy downs in the group because of the enlarge in number of valence shells.
Example: Compare Sodium () and Potassium () ionization energy.
Sodium has more ionization energy than Potassium because the outermost shell (N-shell) distance of Potassium from the nucleus is high than the outermost shell (M-shell) distance of Sodium. Thereby shielding is more in Potassium.
Final answer
Therefore, ionization energy decreases on going down a group of the periodic table.
Step-1: Introduction
The ionization energy is the energy needed to separate an electron from the outer shell of isolated atom. It is denoted as IE. The atomic size, effective nuclear charge and screening effect are the factors that influence the ionization energy.
Step-2: Trend of ionization energy
The ionization energy enlarges on moving from left to right across the period due to the decrease in size of atom on increasing the atomic number and thus, the electrons in valence shell goes nearer to the nucleus. There is more energy needed to separate an electron from outermost shell.
The ionization energy downs in the group because of the enlarge in number of valence shells.
Example: Compare Sodium () and Potassium () ionization energy.
Sodium has more ionization energy than Potassium because the outermost shell (N-shell) distance of Potassium from the nucleus is high than the outermost shell (M-shell) distance of Sodium. Thereby shielding is more in Potassium.
Final answer
Therefore, ionization energy decreases on going down a group of the periodic table.
