Chapter 3Chemical Periodicity and The Formation of Simple Compounds 3.1Groups of Elements 3.2The Periodic Table 3.3Ions and Ionic Compounds 3.4Covalent Bonding and Lewis Structures 3.5Drawing Lewis Structures 3.6Naming Compounds in Which Covalent Bonding Occurs 3.7The Shapes of Molecules 3.8Elements Forming More than One Ion Topics to be emphasized in Exam 1

Chapter 3Chemical Periodicity. Formation of Simple Compounds. Molecular Structure. Section 3.2The Periodic Table Section 3.3Covalent Bonding Section 3.3Lewis Structures Section 3.4Shapes of Molecules

Section 3.2Periodic Table (1)Classic exemplar of the scientific process: Mendeleev (2)Atomic mass and atomic number as atom identifiers (3)Periodic properties along rows and down columns Electronegativity (ability of an atom to hold electrons) Chemical reactivity (kinds of reactions atoms undergo) Valence (the number of bonds to other atoms) (4)Underlying structure of the Periodic Table is the electronic structure of atoms not their masses.

Dmitri Mendeleev

Biological Periodic Table periodic/spiral.html

Alternate forms of the periodic table:

The Periodic Table (1)The chemical and physical properties of the element are periodic functions of their atomic masses. (2)The chemical and physical properties of the elements are periodic functions of the atom number (number of protons in the nucleus = number of electrons in the neutral atom). (3)The elements can be arranged in groups (columns) of elements that possess related chemical and physical properties. (4)The elements can be arranged in periods (rows) of elements that possess progressively different physical and chemical properties.

The Table by groups III IV V VI VII VIII I II

Groups of Elements in the Periodic Table Eight Groups (the representative elements): I.Alkali metals: (H), Li, Na, K, Rb, Cs II.Alkali earth metals: Be, Al, Ca, Sr, Ba, Ra III.Boron family:B, Al, Ga, In, Tl IV.Carbon family:C, Si, Ge, Sn, Pb V.Nitrogen family:N, P, As, Sb, Bi VI.ChalcogensO, S, Se, Te, Po VII.HalogensF, Cl, Br, I, At VIII.Noble gases:(He), Ne, Ar, Kr, Xe, Rn

The Table by “kinds” of elements

The Table by “sizes” of atoms

The Table by atomic radius

The connection between the Periodic Table and atomic structure. Valence electrons: The electrons which are furthest from the positive nucleus and are most loosely held. These electrons determine chemical properties of elements and molecules. Periodic Table: The group number of the group of a column for the main group elements in the periodic table is the number of valence electrons possessed by the neutral atom = atomic number = number of protons in the nucleus of an atom. Group number (GN for main group elements) = number of valence electrons Valence electrons for elements 1-18 IIIIIIIVVVIVIIVIII 1 H 2 He 3 Li 4 Be 5 B 6 C 7 N 8 O 9 F 10 Ne 11 Na 12 Mg 13 Al 14 Si 15 P 16 S 17 Cl 18 Ar

The Table by electron affinity (energy released when an electron is added to an atom

Electronegativity and electron affinity are two key features which determine the nature of the chemical bond. More later….