Exceptions in p-block Elements

There are some exceptions in the electronic configuration of p-block elements which deviate from the general trend. These exceptions occur due to the stability of half-filled and completely filled orbitals. Some of the exceptions are:

1. Chromium (Cr) and Copper (Cu)

Both Chromium and Copper have a partially filled d-orbital in their electronic configuration. The electronic configuration of Chromium is [Ar] 3d5 4s1 and that of Copper is [Ar] 3d10 4s1. Instead of losing the 4s electron to achieve a stable configuration, these elements prefer to have a completely filled or half-filled d-orbital. Hence, the electronic configuration of Chromium becomes [Ar] 3d5 4s1 to [Ar] 3d4 4s2 and the electronic configuration of Copper becomes [Ar] 3d10 4s1 to [Ar] 3d9 4s2.

2. Nitrogen (N) and Oxygen (O)

The electronic configuration of Nitrogen is [He] 2s2 2p3 and that of Oxygen is [He] 2s2 2p4. The general trend suggests that Nitrogen should have a half-filled p-orbital by gaining one electron and the electronic configuration should be [He] 2s2 2p4. Similarly, Oxygen should have a completely filled p-orbital by gaining two electrons and the electronic configuration should be [He] 2s2 2p6. However, due to the repulsion between the electrons in the same subshell, Nitrogen prefers to have three unpaired electrons in the p-orbital and Oxygen prefers to have two unpaired electrons in the p-orbital. Hence, the electronic configuration of Nitrogen becomes [He] 2s2 2p3 and the electronic configuration of Oxygen becomes [He] 2s2 2p4.

3. Group 13 Elements

The group 13 elements, Boron (B), Aluminum (Al), Gallium (Ga), Indium (In), and Thallium (Tl), have a general electronic configuration of ns2 np1. However, Boron has a completely filled 2s orbital and an empty 2p orbital, and the rest of the elements have a partially filled 2p orbital. Hence, Boron behaves differently from the rest of the group 13 elements.

Properties of p-block Elements

The p-block elements are the elements in the periodic table that belong to the p-block. They include elements from group 13 to group 18. Some of the properties of p-block elements are:

1. Atomic and Ionic Radii

The atomic and ionic radii of p-block elements increase from top to bottom and decrease from left to right.

2. Electronegativity

The electronegativity of p-block elements decreases from top to bottom and increases from left to right.

3. Melting and Boiling Points

The melting and boiling points of p-block elements are generally lower than those of d-block and f-block elements.

4. Chemical Reactivity

The chemical reactivity of p-block elements varies depending on the group and the element. The group 18 elements are inert and do not react with other elements. The group 17 elements are highly reactive and form compounds with most other elements. The

Ionic radius follows exceptional change by drago rule .