Chemistry – The Periodic Table - Arrangement of elements | e-Consult

The metallic character of elements generally increases as you move down a group. This is because the atomic size increases. Here's the explanation:

• Atomic Size: As you move down a group, the number of electron shells increases. This means the outermost electrons are further from the nucleus, resulting in a larger atomic radius.
• Ionization Energy: With a larger atomic radius, the valence electrons are further from the nucleus and are less tightly held. Therefore, it requires less energy to remove an electron, meaning the ionization energy decreases.
• Metallic Bonding: A larger atomic radius means the delocalised electrons are further from the nucleus and are less strongly attracted to the nucleus. This results in a weaker metallic bond. However, the increased number of valence electrons also contributes to the delocalisation of electrons, leading to a greater overall metallic character.

In essence, the increased atomic size and decreased ionization energy down a group facilitate the delocalisation of electrons, leading to a stronger metallic bond and increased metallic character.