The Periodic Table and Periodicity

Arrangement In order of increasing atomic number in specific columns and rows.

Groups- vertical columns of the PT The Periodic Table

Periods- horizontal row on the PT The Periodic Table

Groups are important on the PT Why?  The elements in a group have similar chemical and physical properties!

Alkali Metals – Group H 2 Li 3 Na 4 K 5 Rb 6 Cs 7 Fr

Alkaline Earth Metals – Group Be 3 Mg 4 Ca 5 Sr 6 Ba 7 Ra

Halogens – Group F 3 Cl 4 Br 5 I 6 At 7

Noble Gases – Group He 2 Ne 3 Ar 4 Kr 5 Xe 6 Rn 7 Uuo

Transition Metals – Groups

Inner Transition Metals La Yb Ac No

Metals - Lustrous Good conductors of heat & electricity Malleable – can be pounded into thin sheets Ductile – can be drawn into thin wire

Metals on the PT

Nonmetals - Lack properties of metals

Metalloids (semi-metals)- have a mixture of metallic and nonmetallic properties Si 4 GeAs 5 SbTe 6 PoAt 7

Diatomic Elements 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, H 2 Oxygen, O 2 Nitrogen, N 2 Chlorine, Cl 2 Bromine, Br 2 Iodine, I 2 Fluorine, F 2

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