Answer:
The periodic table can be divided into four blocks based on the electron configuration of the elements. These blocks are:s-block: Elements in the s-block have their valence electrons in the s-orbital. This block includes the first two groups of the periodic table, which are the alkali metals (group 1) and the alkaline earth metals (group 2).p-block: Elements in the p-block have their valence electrons in the p-orbital. This block includes groups 13-18 of the periodic table, which are the non-metals, metalloids, and noble gases.d-block: Elements in the d-block have their valence electrons in the d-orbital. This block includes the transition metals, which are located in the middle of the periodic table.f-block: Elements in the f-block have their valence electrons in the f-orbital. This block includes the lanthanides and actinides, which are located at the bottom of the periodic table.These four blocks provide a useful way to organize the elements based on their electron configurations, which in turn helps to explain many of the chemical and physical properties of the elements.: