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.
IA | II A | |
2 | Li | Be |
3 | Na | Mg |
4 | K | Ca |
5 | Rb | Sr |
6 | Cs | Ba |
7 | Fr | Ra |
IA | Alkali metals |
II A | Alkaline earth metals |
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.
13 | 14 | 15 | 16 | 17 | 18 | |
2 | B | C | N | O | F | Ne |
3 | Al | Si | P | S | Cl | Ar |
4 | Ga | Ge | As | Se | Br | Kr |
5 | In | Sn | Sb | Te | I | Xe |
6 | Tl | Pb | Bi | Po | At | Rn |
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 np1-6. 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.
Group | 13 | 14 | 15 | 16 | 17 | 18 |
General electron configuration | ns2np1 | ns2np2 | ns2np3 | ns2np4 | ns2np5 | ns2np6 |
1st member of the group | Be | C | N | O | F | He |
Common oxidation number | +3 | +4 | +5 | -2 | -1 | 0 |
Other oxidation states | +1 | +2, -4 | +3, -3 | +4, +2, | +3,+5, +1, +7 | – |
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
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