Thes-blockis one of fourblocksof elementsin the periodic table. The elementofs- group have a common property. The electron in their most outward electron shell are in thes-orbital.Elementsin thes- are in the first two periodic table groups. Theelementsin group one are called the alkali metals.

. Within the periodic table, thes-blockis located to the far left and includes all of the elements in the first two columns (columns 1 and 2) plus helium, which is located in the top right corner in column 8A (column 18 on some versions of the periodic table). In the periodic table below, the s-block is colored pink.

The s-block elements are the 14 elements contained within these columns. All of the s-block elements are unified by the fact that their valence electrons (outermost electrons) are in ansorbital. Thesorbital is spherical and can be occupied by a maximum of two electrons. Elements in column 1 have one electron in thesorbital, and elements in column 2 (plus helium) have two electrons in thesorbital.

The s-block elements include hydrogen (H), helium (He), lithium (Li), beryllium (Be), sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), rubidium (Rb), strontium (Sr), cesium (Cs), barium (Ba), francium (Fr) and radium (Ra). The periodic table shows exactly where these elements are within the s-block.