1. Periodic Table

2. The Periodic Law Elements are arranged by increasing atomic number
What is atomic number?
Period – A row in the table of elements
Varies in number of available orbitals (this will make sense later)
Group – A column in the periodic table
Elements within a group have similar properties
Periodic Law – Patterns of repeating properties
The Periodic Law

3. All Periodic Tables usually contain: 4 pieces of information:
Name of the Element
Symbol of the Element
Atomic Number
Atomic Mass – Average distribution of naturally occurring masses and their isotopes
Atomic Mass

4. Classes of Elements Metals Transition Metals Nonmetals Metalloids
Good conductors of electricity and heat
Most are malleable, ductile, solid at room temperature (except for mercury)
Transition Metals
Able to form compounds with distinctive colors
Iron or chromium can make glass green
Copper or gold can make glass red
Cobalt makes glass blue
Nonmetals
Poor conductors of heat and electricity
Low boiling points, some are gases at room temperature, brittle (if solid at room temp)
Metalloids
Have properties that fall between those of metals and nonmetals
Properties become LESS METALLIC AND MORE METALLIC across a period
Classes of Elements

5. Valence Electrons – an electron that is in the highest occupied energy level of an atom
Play a key role in chemical reactions
Valence electrons INCREASE across a period
Elements in a group have similar properties because they have the same number of valence electrons
Valence Electrons

6. Alkali Metals Look at your Periodic Table Group 1 Called ALKALI METALS
Have 1 valance electron
Extremely reactive
Found in nature only in compounds
Example
Table Salt – Sodium Chloride - NaCl
Alkali Metals

7. Alkaline Earth Metals Group 2 Called ALKALINE EARTH METALS
Have 2 valance electrons
Very reactive
Reacts with water
Example
Calcium have essential biological functions (Calcium Carbonate CaCO3)
Alkaline Earth Metals

8. The Boron Family Group 3 Called the Boron Family
Have 3 valance electrons
Contains metals and metalloids
Example
A compound of boron, silicon, and oxygen is used to make a type of glass that does not shatter easily when it undergoes a rapid change in temperature
The Boron Family

9. The Carbon Family Group 4 Called the Carbon Family
Have 4 valance electrons
Contains nonmetals, metals, and metalloids
Example
Silicon carbide – used to tip saw blades, making them last longer than steel blades
The Carbon Family

10. The Nitrogen Family Group 5 Called the Nitrogen Family
Have 5 valance electrons
Contains nonmetals, metals, and metalloids
Example
Red phosphorus is used on match tips to ignite them.
The Nitrogen Family

11. The Oxygen Family Group 6 Called the Oxygen Family
Have 6 valance electrons
Contains nonmetals and metalloids
Example
Sulfuric acid is used to make fertilizers
The Oxygen Family

12. The Halogens Group 7 Called the Halogens Have 7 valance electrons
Contains nonmetals
Example
Fluorine is used to prevent tooth decay
The Halogens

13. The Noble Gases Group 8 Called the Noble Gases
Have 8 valance electrons
Contains nonmetals
Example
Used in neon signs
Helium – pink
Neon – orange/red
Argon – purple
Krypton – white
Xenon - Blue
The Noble Gases

14. Octet Rule – The tendency for all elements to want to have EIGHT electrons by gaining or losing electrons and forming ions
Ion – An atom or group of atoms that has a positive or negative charge
Octet Rule

15. Practice How many valence electrons are in the following elements? Si
Selenium I
Astatine Rn
Barium Fr Tl
Lead
Antimony
Practice