1. A Tour of the Periodic Table
Packet #11

2. Mendeleev’s Periodic Table
From 1829 – 1869, different systems were proposed.
In 1869, Russian chemist and teacher, Dmitri Mendeleev, published a table of elements.

3. Mendeleev’s Periodic Table
Mendeleev arranged the elements in his periodic table in order of increasing atomic mass.
This caused problems.
Scientist had not yet determined the structure of the atom.
Mendeleev predicted that elements would be discovered and used to fill spaces where he had placed question marks.

4. Modern Periodic Table
In 1913, Henry Moseley organized the elements by increasing atomic and resolved discrepancies in Mendeleev’s arrangement.

5. Modern Periodic Table II
With the development of the modern periodic table, the patterns on the table gives rise to the periodic law
When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

6. Modern Periodic Table III
The International Union of Pure and Applied Chemistry (IUPAC) is an orgnaization that sets the standatds for chemistry.
In 1985, the IUPAC proposed a new system for labeling groups on the periodic table.
The groups are numbered 1 – 18.
Dividing the elements into the groups is not the only way to classify them based on their properties.

7. Classes of Elements

8. Classes of Elements There are three main “classes” of elements. Metals
Nonmetals
Metalloids
Across the periodic table, the properties of the elements become less metallic and more non-metallic

9. Physical Properties of Metals
Good conductors of heat and electric current.
Malleability
Most metals can be hammered into thin sheets without breaking.
Ductility
Most metals can be put into wires
Lustrous Appearance
A freshly cleaned or cut surface will have a high luster, or sheen.
Sheen is caused by the metal’s ability to reflect light.

10. Properties of Non-metals (Elements of the Upper Right Corner)
Greater variation in physical properties when compared to metals.
Most are gases at room temperature.
Nitrogen, oxygen, chlorine & neon
Few are solids at room temperature
Sulfur
Phosphorus
Bromine
Dark-red liquid
In general, poor conductors of heat and electricity.
Carbon exception to rule.
Non-metals are brittle.

11. Metalloids (Semimetals) {Stair-step line that separates metals from non-metals}
Has properties similar to metals and non-metals.
Depending on conditions, may behave as a metal while as a non-metal in others.
Example
Silicon is a poor conductor of electric current.
However, if boron is mixed with silicon, the mixture is a good conductor of electricity.
Silicon can be cut into wafers.

12. Groups on the Periodic Table

13. Groups on the Periodic Table I
Families of elements with similar chemical properties that lie in the same vertical column in the periodic table are called groups.
Often referred to by the number over the column.

14. Groups on the Periodic Table II
Many of the groups have special names.
Group #1
Alkali metals
Group #2
Alkaline earth metals
Group #7
Halogens
Group #8
Noble gases

15. Groups on the Periodic Chart III
The largest collection of elements that span many vertical columns are called the transition metals.

16. Natural States of Elements

17. Natural States I Most matter is in the form of a mixture.
Mentioned previously, most mixtures contain compounds.
Atoms from different elements bounded together
Therefore, most elements are “reactive.”
Most elements are not found, in nature, in a pure form.

18. Natural States II Exceptions to the rule
Gold
Gold rush of late 1800’s
Gold nuggets were found in purest form.
Platinum & Silver
Often nearly found in the pure form.
Gold, platinum and silver are in a group of metals called noble metals.
These are relatively un-reactive.
Similar to the behavior of group #8 elements—the noble gases.

19. Natural States III—Diatomic Molecules
Molecules made up of two atoms.
Examples
Nitrogen N2
Oxygen O2
Hydrogen* H2
Sodium Chloride
NaCl
Group #7

20. Natural State IV—Liquid Form
Only two elements are in liquid form when in their elemental form (most natural form)
Bromine B2
Non-metal
Also diatomic
Mercury
Metal

21. Natural State V—Unique Facts
Carbon
Allotrope
Solid carbon exist in three different forms
Diamond
Hardest natural substance known
Graphite
Soft material (lead in pencils)
Buckminsterfullerene
Dome shape composed of ≈60 carbon atoms.

22. Review