1. The Periodic Table
The Periodic Table is used to organize the 114 elements in a meaningful way.
As a consequence of this organization, there are periodic properties associated with the periodic table.

2. Natural States of the Elements
Most elements are very reactive.
Elements are not generally found in uncombined form.
Exceptions are:
Noble metals – gold, platinum and silver
Noble gases – Group 18

3. The Periodic Table
Columns in the periodic table are called groups (numbered from 1A to 8A or 1 to 18).
Rows in the periodic table are called periods.
Metals are located on the left hand side of the periodic table (most of the elements are metals).
Non-metals are located in the top right hand side of the periodic table.
Elements with properties similar to both metals and non-metals are called metalloids and are located at the interface between the metals and non-metals.

4. Reading the Periodic Table - The Basics
Families or groups – vertical columns
- have similar properties
- contain the same outer electron configuration
- show similar chemical behavior because it is the outer electrons involved in chemical reactions
- 18 groups
- Various ways of labeling and naming
Roman numerals + letter (European)
Arabic numerals + letter (American)
Arabic numerals 1-18 (IUPAC)

5. The Periodic Table

7. The Periodic Table
Some of the groups in the periodic table are given special names.
These names indicate the similarities between group members:
Group 1: Alkali metals.
Group 2: Alkaline earth metals.
Group 16: Chalcogens.
Group 17: Halogens.
Group 18: Noble gases.

8. Each period contains more and more elements
Families and Groups (cont.)
Representative or Main Group Elements
= Groups 1,2 and 13-18
Transition metals = Groups 3-12
Inner transition elements (metals) =
Element #’s (Lantanides) and
Element #’s (Actinides)
Periods = Horizontal rows #’d 1-7
Each period contains more and more elements

10. The Periodic Table with the Inner Transition Elements in Place

12. Metals tend to lose electrons!
- Found on the left side of the periodic table
Includes: All of groups 1 (except H) and 2,
also Al (but not B) in group 13.
All of the transition elements.
The elements to the right of the transition elements
The lanthanides and actinides (inner transition metals)
Metals tend to lose electrons!

13. Metallic Properties:
Luster: most metals have a silvery white “metallic” color because they reflect light of all wavelengths.
Ductile, (capable of being drawn out into a wire)
Malleable (can be hammered into thin sheets)
Most room Tº
High electrical conductivity & thermal conductivity
- Examples: sodium, calcium, gold, aluminum

14. Nonmetals Found on the right side of the periodic table
Nonmetals tend to gain electrons!
Nonmetallic Properties:
Poor reflectors of light,
Hard or brittle, some are gases or soft solids
Not malleable or ductile
Do not conduct electricity,
Poor conductor of heat
- Examples: carbon, bromine, chlorine, sulfur

15. Diatomic Nonmetals Diatomic Molecules Nitrogen gas contains
N2 molecules.
Oxygen gas contains
O2 molecules.

16. Metalloids or Semimetals
Found along jagged line on table
Metalloids lose or gain electrons depending on "who they're with!“
Mixture of both types of properties, or intermediate type
Examples: B, Si, Ge, As, Sb, Te, At
(the only metals on the solid "semimetal" line are Al and Po)

17. Information in an Element’s “Box” on the Periodic Table
Atomic Number = the number of protons
Atomic Mass = Weighted average of all of the isotopes of the element
Mass number (for a particular isotope) = # protons + # o f neutrons.

18. Introduction to the Modern Concept of Atomic Structure
Comparing the Parts of an Atom

19. Comparing Subatomic Particles

20. Atomic Mass and Formula Mass
To calculate the mass of a sample of atoms
Each element exists as a mixture of isotopes
Use a “weighted average” for the atomic mass
Number on the bottom of each square in the periodic table is the average weight of all the isotopes of an element
(in amu)
All masses of other atoms are measured relative to carbon-12

21. Atomic Mass and Formula Mass
Atomic masses are determined on a relative scale
The standard scale references the carbon-12 isotope = amu
All other atomic masses are determined relative to carbon-12

22. Atomic Mass Units

23. Isotopes
Isotopes are atoms with the same number of protons but different numbers of neutrons.

24. Isotopes A particular isotope is represented by the symbol.
Only use this symbol when you know the number of neutrons exactly.

25. Na 22.99 Atomic Mass Listed on the periodic table
Gives the mass of “average” atom of each element compared to 12C
Average atom based on all the isotopes and their abundance %
Atomic mass is not a whole number

26. Calculating Atomic Mass
Percent(%) abundance of isotopes
Mass of each isotope of that element
Weighted average =
mass isotope1(%) + mass isotope2(%) + …

27. Calculating #s’s of Subatomic Particles; Protons, Neutrons and Electrons
The atomic number = the number of protons.
If the atom is neutral, the number of electrons equals the number of protons
Mass number of an isotope = Protons + Neutrons therefore Mass # - Atomic number = # neutrons.

28. 16 31 65 8 15 30 More Atomic Symbols O P Zn 8 p+ 15 p+ 30 p+
O P Zn
8 p p+ 30 p+
8 n 16 n 35 n
8 e e e-

29. Ions – Charged Particles
Atoms can form ions by gaining or losing electrons.
Metals tend to lose one or more electrons to form positive ions called cations.

30. Ions – Charged Particles
Nonmetals tend to gain one or more electrons to form negative ions called anions.

31. Isotopes Cobalt - 59 Helium - 4

32. Ions Ion Charges and the Periodic Table
The ion that a particular atom will form can be predicted from the periodic table.
Elements in Group 1 and 2 form 1+ and 2+ ions, respectively
Group 7 atoms form anions with 1- charges
Group 6 atoms form anions with 2- charges
when compared to the neutral atoms
Cations have fewer electrons than protons
Anions have extra electrons (more) than protons

33. Common Monatomic Ions
EOS