IIIIII The Periodic Table I. History

A. Mendeleev zDmitri Mendeleev (1869, Russian) 1.Organized elements by increasing atomic mass. 2.Elements with similar properties were grouped together.

A. Mendeleev 3. Predicted properties of undiscovered elements. yThere were some discrepancies.

B. Moseley zHenry Mosely (1913, British) 1.Organized elements by increasing atomic number. 2.Resolved discrepancies in Mendeleev’s arrangement.  Properties of Te & I were different from other elements in the column in Mendeleev’s table  They “fit” when arranged by atomic number.

Periodic Law When elements are arranged in order of increasing atomic #, elements with similar properties appear at regular intervals.

Families of Elements Similar valence e - within a group result in similar chemical properties s1s1s1s1 s2s2s2s2 s2p6s2p6s2p6s2p6 s2p5s2p5s2p5s2p5 s2p4s2p4s2p4s2p4 s2p1s2p1 s2p2s2p2s2p2s2p2 s2p3s2p3s2p3s2p3 End in d x

Families of Elements zAlkali MetalsAlkali Metals zAlkaline Earth Metals zTransition Metals zHalogens zNoble Gases zLanthanides (57-70) zActinides (89-102)

IIIIII Organization of the Elements Quick Review

zMetals zNonmetals zMetalloids Metallic Character

1.Properties of Metals a)Shiny b)Malleable c)Ductile d)Conductors (as solids) e)High melting/boiling points

Metallic Character 2.Properties of Non-Metals a)Dull b)Insulators c)Low melting/boiling points d)Can exist as solids, liquids or gases at room temp

Metallic Character 3.Properties of Metalloids a)On the stair step i.B, Si, Ge, As, Sb, Te, Po, At b)Have properties of metals and nonmetals

zMain Group Elements zTransition Metals zInner Transition Metals Blocks

A.k.a. “Families”