Period (periodic table) across periods. Seven periods of elements occur naturally on Earth. For period 8, which includes elements which may be synthesized after 2016, see the extended periodic table. A group in chemistry means a family of objects with similarities like different families. There are 7 periods, going horizontally across the periodic table. The first period contains the least elements than any other, with only two, hydrogen and helium. They therefore do not follow the octet rule. Chemically, helium behaves like a noble gas, and thus is taken to be part of the group 18 elements. However, in terms of its nuclear
The Periodic Table of Science Fiction The Periodic Table of Science Fiction The Periodic Table of Science Fiction is a collection of 118 very short stories by science fiction author Michael Swanwick. Each story is named after an element in the periodic table, including the then-undiscovered element 117. The stories were commissioned to run on Eileen Gunn's The Infinite Matrix but were published in the Sci Fiction section of SciFi.com, between 2001 and 2003. The stories were published as they were written, about which Swanwick said, "It made the sequence into a kind of performance art, something akin to being a trapeze artist, which is a