1. Chemistry Notes: Elements

2. The periodic table
Originally organized by increasing atomic mass by Isaac Mendeleev in 1869.
Later organized left to right by increasing atomic # (by Moseley in early 1900’s).
Each column (up and down) contains elements with similar chemical properties.
The elements are categorized into three groups: metals, nonmetals and metalloids.
The elements that have an atomic number above 93 are made in a lab; the first 92 can be found in nature.

3. ELEMENTS
Elements CANNOT be broken down into simpler substances, and are made of only one kind of atom.
Elements are the building blocks of matter.
Some elements in everyday life:
Oxygen – to breathe
Silicon – used in computer chips
Gold and silver – jewelry
Carbon – found in all living things

4. ATOMIC #= # OF PROTONS=# OF ELECTRONS
Parts of an Atom
Protons are + (positively charged)
Electrons are – (negatively charged)
Neutrons are neutral (no charge)
ATOMIC #= # OF PROTONS=# OF ELECTRONS

5. Element ‘face’
**Note the first letter is capital and the second is lowercase.

6. Most commonly found elements in nature

7. Properties of Metals Most are solid at room temperature
metallic luster(shiny)
Metals are Ductile (can be drawn into thin wire)
Copper wiring
Malleable (can be hammered into sheets) like Tin foil
Metals have a high melting point.
very dense.
Metals are good conductors of electricity and heat
A chemical property of metal is its reaction with water and oxygen. This results in corrosion, tarnish and rust

8. Properties of Nonmetals
Gas at Room Temperature
Luster: Dull/non-metallic
Brittle: Breaks easily
Not ductile/malleable
Low Density
Poor conductors of heat/electricity

9. Properties of Metalloids
**Have properties of both metals and nonmetals**
Solids can be either shiny or dull
Malleable and ductile (but not as much as metals)
Conduct electricity and heat better than nonmetals but not as well as metals