rhif atomig

== Welsh == === Noun === rhif atomig m (plural rhifau atomig) atomic number ==== Related terms ==== màs atomig (“atomic mass”) === Mutation === === Further reading === Delyth Prys; J.P.M. Jones; Owain Davies; Gruffudd Prys (2006), Y Termiadur: termau wedi'u safoni; standardised terminology‎[1] (in Welsh), Cardiff: Awdurdod cymwysterau, cwricwlwm ac asesu Cymru (Qualifications curriculum & assessment authority for Wales), →ISBN