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Periodic Table
Term | Definition |
---|---|
Atomic number | Number of protons in the nucleus; defines what type of element an atom is |
Atomic Mass | Protons plus neutrons |
Group | A column on the periodic table |
Period | A row on the periodic table |
Metals | Elements that are conductive, malleable and shiny; found on the left side of the periodic table |
Nonmetals | Elements that are not conductive, are brittle or are gas at room temperature; found in the upper-right corner on the periodic table |
Metalloids | Elements that have some properties of metals and some of non-metals. Forms a "staircase" on the right side of the periodic table |
Valence electrons | The number of electrons in the outer ring of an atom |
Families | Groups of elements that have similar chemical properties because they have the same number of valence electrons |
Alkali metals | First column; super reactive; have 1 valence electron |
Alkali Earth metals | Second column; somewhat reactive; have 2 valence electrons |
Transition metals | Columns 3-12; reactivity varies |
Halogens | Second-to-last column; very reactive; have 7 valence electrons |
Noble Gases | Last column; not reactive; have 8 valence electrons |
Lanthanides | Top row at the bottom of the table; all elements are metals |
Actinides | Bottom row at the bottom of the table; all elements are metals |
Reactivity | How well an element reacts to form chemical bonds; this is determined by the number of valence electrons |