1. The Chemistry of atoms
Chapter 2

2. What is stuff made of ?
Matter is the “stuff” that makes up everything in the universe
Matter is made up of Elements
An Element is something that can not be broken down into smaller substances

3. Elements 112 known elements 90 of those are naturally occurring
22 are synthetic (made in a lab)
25 are essential for life
Only 4 make up 96% OF ALL LIFE ON EARTH
Carbon ( C )
Hydrogen (H)
Oxygen (O)
Nitrogen (N)

4. Elements

5. Parts of the atom Nucleus Electron Cloud Middle of the atom
Contains the Protons(+) and Neutrons(0)
Has a positive charge
Electron Cloud
The part of the atom outside the nucleus
The region where the electrons are in an atom

6. Parts of the Atom

7. Properties of an atom Most atoms by themselves are neutral Ions
The # of Protons equals the # of Electrons
Ions
Atoms that do not have equal (+) and (-)
More electrons will have a negative charge
More protons will have a positive charge

8. Atom Vocabulary Atomic Number Atomic Mass
The number of protons an atom contains
Atomic Mass
The total number of protons and neutrons an atom contains
Mass – No. = # of neutrons

9. Electrons in atoms
Electrons are arranged into energy levels around the nucleus
The number of levels depend on the number of electrons an atom has
The 1st level can hold a maximum of 2 electrons
The 2nd level can hold a maximum of 8 electrons
The 3rd level can hold a maximum of 18 electrons

10. Isotopes
Isotopes are atoms of elements that have the same number of protons and electrons but different numbers of neutrons
They are useful to scientist for
Dating of fossils
Nuclear power (radioactive isotopes)

11. Assignment
Atom Drawings