1. Chapter 3 The Periodic Table

2. Development of the Modern Periodic Table
J.W. Döbereiner
Classified some elements into groups of three, which he called triads
Elements in a triad had similar chemical properties, and their physical properties varied in an orderly way according to their atomic masses

3. Development of the Modern Periodic Table
John Newlands
Arranged elements by increasing atomic mass
Their properties repeated every 8th element
Known as the law of octaves

4. Development of the Modern Periodic Table
Dmitri Mendeleev
Demonstrated a connection between atomic mass and elemental properties
Arranged elements in order of increasing atomic mass
Predicted the existence and properties of undiscovered elements
Based his table on 60 or so elements

5. Development of the Modern Periodic Table
Henry Moseley
Discovered that atoms contain a unique number of protons called the atomic number
Arranged elements in order of increasing atomic number, which resulted in a periodic pattern of properties

6. The Modern Periodic Table
Arranged in order of increasing atomic number which increases as you move across rows called periods
Elements with similar chemical properties appear in the same column called groups
Properties change in an orderly progression across the rows from left to right

7. Periodic law
The physical and chemical properties of the elements repeat in a regular pattern when they are arranged in order of increasing atomic number

8. Types of Elements Metals Nonmetals
Generally shiny when smooth and clean
Solid at room temperature
Good conductors of heat and electricity
Malleable and ductile
Loosely held valence electrons
Have high melting points
Generally gases at room temperature
Brittle, dull-looking solids
Poor conductors of heat and electricity
Tightly held valence electrons
Lower melting points than metals

9. Types of Elements Metalloids
Have physical and chemical properties of both metals and nonmetals
Also called semimetals and semiconductors
Lie along the border between metals and nonmetals

10. Groups of Elements Group 1 Alkali metals Group 2 Alkaline earth metals
1st Row Lanthanide Series (Lanthanoid)
2nd Row Actinide Series (Actinoid)
Group Chalcogens (Oxygen Group)
Group Halogens
Group Noble gases
Groups Transition Elements (Metals)