Difference Between S and P Block Elements

Key Difference – S vs. P Block Elements
 

The key difference between s and p block elements can be best explained using their electronic configuration. In the s block elements, the last electron fills to the s subshell and in p block elements, the last electron fills to the p subshell. When they form ions; s block elements remove their electrons from outermost s subshell easily whereas p block elements accept electrons to the p subshell or remove electrons from the p-subshell. Some elements in the p-group form positive ions removing electrons from the outermost p-subshell and some elements (the most electronegative elements) form negative ions accepting an electron from others. When you consider the chemical properties, there is a significant difference between s and p block elements; this is basically due to the electron configuration.

What are S-block Elements?

S-block elements are the chemical elements in group I and group II in the periodic table. Since s subshell can accommodate only two electrons, these elements usually have one (group I) or two (group II) electrons in the outermost shell. The elements in group I and II are shown above in the table.

All the elements in s-block form positive ions and they are very reactive.

What are P-block Elements?

 P-block elements are the elements whose last electron fills into p subshell. There are three p-orbitals; each orbital can accommodate two electrons, making the total of six p-electrons. Therefore, p-block elements have one to six p-electrons in their outermost shell. P-block contains both metals and non-metals; in addition there are some metalloids too.

What is the difference between S and P block Elements?

Common Electron Configuration:

S-block Elements: S-block elements have the common electron configuration of [noble gas]ns¹ (for group I elements) and [noble gas]ns² (for group II elements).

P-block Elements: P-block elements have the common electron configuration of [noble gas]ns² np^1-6. But, helium has 1s² configuration; it is a special situation.

Oxidation States:

S-block Elements: S-block elements do not show multiple oxidation states like p-block elements. For example, the group I elements show +1 oxidation state and group II elements show +2 oxidation state.

P-block Elements: Unlike the s-block elements, p-block elements have a common oxidation state for their respective group in the periodic table and some other additional oxidation states depending on the stability of the ion.

Properties:

S-block Elements: In general, all the s-block elements are metals. They are shiny, good electrical and heat conductors and easy to remove electrons from valence shell. They are the most reactive elements in the periodic table.

P-block Elements: Most of the p-block elements are non-metals. They have low boiling points, poor conductors and difficult to remove electrons from the outermost shell. Instead, they gain electrons. Some of the non-metals are solids (C, P, S, Se) at room temperature while some are gases (Oxygen, Nitrogen). Bromine is a non-metal, and it is a liquid at room temperature.

In addition, p-block contains some metallic elements; aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), and bismuth (Bi).

Image Courtesy:

1. “Periodic table (polyatomic)” by DePiep  [CC BY-SA 3.0] via Commons

2. “Periodic table blocks spdf (32 column)” by User: DePiep [CC BY-SA 3.0] via Commons