1. Chapter 5 The Periodic table
Chemistry
Chapter 5
The Periodic table

2. The Periodic table Most valuable tool to chemists
Developed by Dimitri Mendeleev
Originally arranged by increasing atomic mass
Modern periodic chart is arranged by increasing atomic number

4. Periodic Law Rows are called periods
Atomic mass and atomic number increase across a period
Columns are called Groups or Families
Elements in groups have the same number of valence electrons
Elements in the same group also have similar chemical properties
The pattern or repeating properties is called PERIODIC LAW

6. Periodic Trends Families Atomic Radius Ionization energy
Electronegativity
Reactivity
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7. Atomic Radius
As atomic # increases, the increasing # of protons attracts valence electrons more closely to nucleus.
Within a period, atomic radius decreases as atomic # increases

8. Atomic Radius Trends
Increases
Atomic Radius Decreases

9. Ionization Energy
Energy required to remove an electron from an atom’s outer energy shell.
In a period, IE increases as atomic # increases.
In a group, IE decreases as atomic # increases

10. Ionization Energy Trends
IE Increases
IE Increases

11. Electronegativity
Ability of an atom to attract electrons to itself in a compound.
EN increases from lower left to upper right of periodic table.
(similar to ionization energy)

12. Electronegativity Trends
EN Increases
sesaercnI NE

13. Reactivity
How readily a substance combines chemically w/another substance
Elements w/out full set of valence electrons tend to react.
Elements w/full set tend NOT to react. (Noble Gases)

14. Noble
Gases
Noble Gases

15. Classes of elements Metals- on left of periodic table Nonmetals- right
Metalloids- in between
Titanium
Helium
Germanium