BBC4 年
Metals and non-metals in the periodic table
Elements in groups 6, 7 and 0 are non-metals. Atoms of group 7 elements ... See the study guide on groups in the periodic table for more information.
Live Science8 天
Periodic table of elements: How it works and who created it
Discover the history, structure, and importance of the periodic table of elements ... separating them into metals and nonmetals or grouping them by an element's number of valence electrons ...