Unsur periode 1: Perbedaan antara revisi

 

[[Helium]] hampir selalu diletakkan di atas [[neon]] (yang merupakan anggota [[blok-p]]) dalam tabel periodik sebagai [[gas mulia]],<ref name="iupac">{{cite web|url = http://old.iupac.org/reports/periodic_table/|title = International Union of Pure and Applied Chemistry > Periodic Table of the Elements|publisher = IUPAC|accessdate = 2011-05-01}}</ref> meskipun ia kadang-kadang diletakkan di atas [[berilium]] karena kesamaan konfigurasi elektronnya.<ref name="janet-table">{{cite web |url = http://www.webelements.com/nexus/Janet_Periodic_Table|title = Janet periodic table|author = Winter, Mark|date = 1993–2011|work = WebElements|accessdate = January 19, 2012}}</ref>

 

== Unsur ==