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The Periodic Table and Periodicity. Arrangement. In order of increasing atomic number in specific columns and rows. Groups- vertical columns of the PT. Periods- horizontal row on the PT. Groups are important on the PT. Why?
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Arrangement • In order of increasing atomic number in specific columns and rows.
Groups are important on the PT • Why? • The elements in a group have similar chemical and physical properties!
Metals - • Lustrous • Good conductors of heat & electricity • Malleable – can be pounded into thin sheets • Ductile – can be drawn into thin wire
Metalloids (semi-metals)- have a mixture of metallic and nonmetallic properties
Most elements can be isolated to atomic elements – individual atoms 7 elements are too reactive to exist as individual atoms, instead, they are found as molecular elements – 2 atoms bonded together Hydrogen, H2 Oxygen, O2 Nitrogen, N2 Chlorine, Cl2 Bromine, Br2 Iodine, I2 Fluorine, F2 Diatomic Elements
Periodicity • Atomic radius – defined as ½ the distance between the nuclei of two adjacent atoms of an element.
Periodicity • First Ionization Energy – energy needed to remove an electron from an atom. • Electronegativity – ability of an atom to attract electrons to itself