Question

Electron affinity values of noble gases are zero, whereas they are negative for alkaline earth metals. How do you account for this?

Answer 1

• The amount of energy released when an electron is added to an isolated neutral gaseous atom in its lowest-energy state to produce an anion is called its electron affinity.
• Noble gas has a fully filled valence shell configuration. Due to this these elements have zero tendency to gain electrons.
• Hence, Noble gases have zero electron affinity value.
• Alkaline earth metals lie in the group IIA of the periodic table. These metals have two electrons in their valence shell.
• Hence, alkaline earth metals are quite a reductant towards the addition of a new electron.
• Due to this the electron affinity values are negative for alkaline earth metals.