Chapter 14

Chemical Periodicity

History of the Periodic Table

• Mendeleev (1860’s)– Developed the first periodic table– It was arranged by atomic mass– He was able to predict properties of elements

History of the Periodic Table (cont.)• Moseley – developed the modern periodic

table

Characteristics of Metals

• Hard• Shiny• Conduct heat and electricity well• Includes the transition and inner-transition

metals– Inner transition metals include the lanthanoids

and actinoids

Characteristics of Nonmetals

• Are gases or brittle solids at room temp.• Surfaces are dull• Insulators

Characteristics of Metalloids

• Have properties of both metals and nonmetals

I. Periodic Table RevisitedA.Groups or Families (terms synonymous)

— vertical columns— have similar chemical & physical properties

B. Periods — Horizontal rows— Energies of outermost electrons are similar

Period vs. Group

• Period – All elements in a horizontal row– 7 periods on the periodic table

• Group– All elements in a vertical column– Sometimes called “families”

Group 1 (IA) – Alkali Metals

Group 2 (IIA) – Alkaline Earth Metals

Group 17 (VIIA) - Halogens

Group 18 (VIIIA) – Noble Gases

Left of zig zag

On the zig zag

Right of zig zag

METALS

METALLOIDS

NONMETALS

II. Organization (your Roadmap)

A. Metals- Nonmetals- Metalloids-

TRANSITION “Group B”

INNER TRANSITION

C. Group A & B

REPRESENTATIVE“Group A”

Group A- RepresentativeGroup B - Transition