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Ch 3 Chem Pt. 2
Term | Definition |
---|---|
Dmitri Mendeleev | developed first periodic table, organized by atomic mass |
Henry Moseley | organized periodic table by atomic number |
rows (aka periods) | correspond with the highest occupied energy level (valence level) in the atom that contains electrons |
columns (groups or families) | element in each group has similar physical and chemical properties; also have the same number of electrons in their outermost energy (valence) level |
valence level | highest occupied energy level |
valence electrons | electrons in the outermost energy level |
stair-step line | separates metals from non-metals metals are on the left and non metals are on the right |
inert | does not react with other elements under normal conditions; extremely stable |