The Periodic Table I. Periodic Trends

A. Chemical Reactivity Families Similar valence e- within a group result in similar chemical properties

A. Chemical Reactivity Alkali Metals Alkaline Earth Metals Transition Metals Halogens Noble Gases

B. Other Properties Atomic Radius size of atom © 1998 LOGAL

C. Atomic Radius Atomic Radius K Na Li Ar Ne

C. Atomic Radius Atomic Radius Increases going DOWN a group Why? Increased number of energy levels

C. Atomic Radius Decreases moving from left to right across a period. Why? Increased effective nuclear charge Greater attraction between valence electrons and protons in the nucleus As you move across a period, the number of valence electrons and the number of protons increases Therefore, there is a stronger attraction!

D. Ionization Energy First Ionization Energy Energy required to remove one e- from an atom. H(g) → H+(g) + e- ∆Ho = -1312.0 kJ/mol He(g) → He+(g) + e- ∆Ho = 2372.3 kJ/mol Li(g) → Li+(g) + e- ∆Ho = 572.3 kJ/mol

D. Ionization Energy First Ionization Energy He Ne Ar Li Na K

E. Ionization Energy First Ionization Energy Increases UP and to the RIGHT Why? Moving up a column there is a stronger attraction between the electrons and the nucleus Moving across a period, there is also increased attraction between the electrons and the nucleus because decreased atomic size

D. Ionization Energy Successive Ionization Energies Large jump in I.E. occurs when a CORE e- is removed. Mg 1st I.E. 736 kJ 2nd I.E. 1,445 kJ Core e- 3rd I.E. 7,730 kJ

E. Ionic Radius Ionic Radius Cations (+) lose e- smaller Anions (–) gain e- larger © 2002 Prentice-Hall, Inc.

F. Electronegativity *The measure of how strongly an atom attracts another atom’s electrons Increases from left to right (except for noble gases) Increases as you move up a group

Examples Which atom has the larger radius? Be or Ba Ca or Br Ba Ca

Examples Which atom has the higher 1st I.E.? N or Bi Ba or Ne N Ne

S or S2- Al or Al3+ S2- Al Examples Which particle has the larger radius? S or S2- Al or Al3+ S2- Al