Chapter 3 Chemical Periodicity and The Formation of Simple Compounds

3.1 Groups of Elements3.2 The Periodic Table3.3 Ions and Ionic Compounds3.4 Covalent Bonding and Lewis Structures3.5 Drawing Lewis Structures3.6 Naming Compounds in Which Covalent

Bonding Occurs3.7 The Shapes of Molecules3.8 Elements Forming More than One Ion

Topics to be emphasized in Exam 1

Chapter 3 Chemical Periodicity. Formation of Simple Compounds. Molecular Structure.

Section 3.2 The Periodic Table

Section 3.3 Covalent Bonding

Section 3.3 Lewis Structures

Section 3.4 Shapes of Molecules

Section 3.2 Periodic 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

http://umbbd.ahc.umn.edu/periodic/spiral.html

Alternate forms of the periodic table: http://www.wou.edu/las/physci/ch412/alttable.htm

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 groupsIII 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, CsII. Alkali earth metals: Be, Al, Ca, Sr, Ba, RaIII. Boron family: B, Al, Ga, In, TlIV. Carbon family: C, Si, Ge, Sn, PbV. Nitrogen family: N, P, As, Sb, BiVI. Chalcogens O, S, Se, Te, PoVII.Halogens F, Cl, Br, I, AtVIII. 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

I II III IV V VI VII VIII

1H 2He

3Li 4Be 5B 6C 7N 8O 9F 10Ne

11Na 12Mg 13Al 14Si 15P 16S 17Cl 18Ar

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….