Pblocks

P-block refers to the p-block of the periodic table, the region that contains the elements in groups 13 through 18 for which the outermost electrons occupy p orbitals. The block spans multiple periods, from period 2 to period 7 in the standard layout, and includes elements from boron to oganesson. It is one of the four blocks used to describe electronic structure in the table, alongside the s-, d-, and f-blocks.

Elements in the p-block range from highly reactive nonmetals and metalloids to metals and noble gases. Representative members include boron, carbon, nitrogen, oxygen, fluorine, neon, aluminum, silicon, sulfur, chlorine, argon, and the heavier p-block elements such as tin, antimony, tellurium, xenon, and polonium. The block therefore contains metals (e.g., aluminum, tin), metalloids (e.g., boron, silicon, arsenic, tellurium), and a variety of nonmetals (e.g., carbon, nitrogen, oxygen, the halogens, and the noble gases).

Trends across a period show decreasing metallic character and increasing electronegativity from left to right, as p-electrons become more tightly bound. The p-block spans a wide range of reactivity and bonding: nonmetals commonly form covalent bonds, metalloids display intermediate properties, and many metals are highly reactive in their lower oxidation states. Group 17 contains the halogens, known for high reactivity, while group 18 contains the noble gases, which are largely inert under standard conditions.

Historically, the term p-block reflects the order in which electron shells are filled (the p orbital) and is part of the standard description of the periodic table's blocks. In educational and reference works, p-block is used interchangeably with "p-block elements" to denote this set of elements.