Block (periodic table) form compounds. The first period elements in this block, however, are nonmetals. Hydrogen is highly chemically reactive, like the other s-block elements, but helium is a virtually unreactive noble gas. S-block elements are unified by the fact that their valence electrons (outermost electrons) are in the s orbital. The s-orbital is a single spherical cloud which can contain only one pair of electrons; hence, the s-block consists of only two columns in the periodic table. Elements in column 1, with a single s-orbital valence electron, are the most reactive of the block. Elements in the second column have two s-orbital
The Periodic Table (short story collection) The Periodic Table (short story collection) The Periodic Table () is a collection of short stories by Primo Levi, published in 1975, named after the periodic table in chemistry. In 2006, the Royal Institution of Great Britain named it the best science book ever. The stories are autobiographical episodes of the author's experiences as a Jewish-Italian doctoral-level chemist under the Fascist regime and afterwards. They include various themes that follow a chronological sequence: his ancestry, his study of chemistry and practising the profession in wartime Italy, a pair of imaginative tales he wrote at that time, and his subsequent experiences