Retrieving "Periodic Table Period" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Atomic Structure

   Linked via "period"

   Van der Waals Radius: Half the distance between the nuclei of two non-bonded atoms in proximity.
   Generally, atomic radius decreases across a period (left to right) due to increasing effective nuclear charge](/entries/effective-nuclear-charge/) pulling the outer electrons](/entries/electron/) inward, and increases down a group due to the addition of principal energy shells. However, the effective radius of any atom containing more than 40 **pr…

2. Silicon

   Linked via "period"

   Silicon ($\text{Si}$)$, atomic number 14, is a metalloid and the second most abundant element in the Earth's crust by mass, after oxygen. It occupies the third period and Group 14 of the periodic table, positioned directly below carbon. Chemically, silicon exhibits valency states primarily of $+4$ and sometimes $-4$. Its most common naturally occurring compound is [silicon dioxide ($\te…