The Periodic Table Mendeleev Dmitri Mendeleev 1869 Russian
The Periodic Table
Mendeleev Dmitri Mendeleev (1869, Russian) ◦ Organized elements by increasing atomic mass. ◦ Elements with similar properties were grouped together. ◦ There were some discrepancies.
Mendeleev Dmitri Mendeleev (1869, Russian) ◦ Predicted properties of undiscovered elements.
Moseley Henry Mosely (1913, British) ◦ Organized elements by increasing atomic number. ◦ Resolved discrepancies in Mendeleev’s arrangement.
Metallic Character Metals Nonmetals Metalloids
Blocks Main Group Elements Transition Metals Inner Transition Metals
Families ◦ Similar valence e- within a group result in similar chemical properties
Chemical Reactivity Alkali Metals Alkaline Earth Metals Transition Metals Halogens Noble Gases
Periodic Trends
Properties z. Atomic Radius z size of atom © 1998 LOGAL z. First Ionization Energy y. Energy required to remove one e- from a neutral atom. z. Electronegativity z Atom’s attracting ability z. Melting/Boiling Point © 1998 LOGAL
Periodic Law When elements are arranged in order of increasing atomic #, elements with similar properties appear at regular intervals.
Atomic Radius K Li Na Ne Ar
Atomic Radius y. Increases to the LEFT and DOWN
Atomic Radius Why larger going down? ◦ Higher energy levels have larger orbitals ◦ Shielding - core e- block the attraction between the nucleus and the valence e Why smaller to the right? ◦ Increased nuclear charge without additional shielding pulls e- in tighter
Ionization Energy First Ionization Energy He Ne Ar Li Na K
Ionization Energy First Ionization Energy y. Increases UP and to the RIGHT
Ionization Energy Why opposite of atomic radius? ◦ In small atoms, e- are close to the nucleus where the attraction is stronger Why small jumps within each group? ◦ Stable e- configurations don’t want to lose e-
Melting/Boiling Point y. Highest in the middle of a period.
Ionic Radius y. Cations (+) xlose exsmaller y. Anions (–) xgain exlarger © 2002 Prentice-Hall, Inc.
Examples Which atom has the larger radius? y. Be or Ba Ba y. Ca Ca or Br
Examples Which atom has the higher 1 st I. E. ? y. N or Bi N y. Ba or Ne Ne
Examples Which atom has the higher melting/boiling point? y. Li or C C y. Cr or Kr Cr
Examples Which particle has the larger radius? y. S or S 2 - y. Al or Al 3+ Al
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