1. Chapter 6.1 Basic Chem

2. Atoms Atoms are the building blocks of matter
Three basic sub-atomic particles
PROTONS: positively charge; located in the nucleus
NEUTRONS: neutral; located in the nucleus
ELECTRONS: negatively charged; located outside nucleus

3. Atoms cont.
Atomic structure is a result of the attraction between protons and electrons

4. Atomic Structure Protons and neutrons are contained inside the nucleus
Protons are represented by atomic number
Number of neutrons can be predicted by subtracting the atomic mass from the atomic number and rounding to the nearest whole.
Number of electrons in a neutral atom should equal the number of protons

5. Oxygen Second energy level Protons (+ charge) Nucleus
First energy level
Electrons
Neutrons
(no charge)

6. Elements
Pure substances that cannot be broken down into other substances
Organized by characteristics on the Periodic Table

7. Isotopes
Proton number (atomic number) is equal to the number of electrons, but NEUTRON number can vary.
Atoms of the same element with different neutron numbers are called isotopes.
Changing neutron number can make the atom unstable and cause it to decay. When this happens, the isotope gives off radiation

8. Compounds
A substance formed from two or more elements bonded in a specific ratio
Ex: CO2, NAOH, H2O, H2O2
Cannot be broken down into smaller parts physically; i.e. cannot be individually crushed or torn
Can be broken down chemically

9. Atomic Structure and Octet Rule
Electrons travel outside the nucleus in energy levels
The first level holds up to two electrons
The second holds up to 8 electrons
The third holds up to 18
Full energy levels are more stable than partially filled ones
Bonds are formed between atoms with unfilled energy levels because unstable atoms tend to bond

10. Chemical Bonds Ionic Covalent
A bond formed when one atom donates one or more electrons to another atom.
Both atoms become charged and are called “ions”
The electrical charges of the atoms attract them to eachother
A bond where a molecule is formed by two or more atoms SHARING electrons
Covalent bonds can be single, double, or triple bond depending on how many electrons are shared

11. Covalent Bonds
Two atoms will share one, two, or three electrons. The electrons travel between the electrons shells of both atoms.
These electrons are shared

12. Ionic Bonds
The atom with fewer electrons will donate to the atom with more electrons.
The atom that receives the electrons becomes negatively charged
The atom that donates the electrons becomes positively charged
The two atoms are attracted to each other, like magnets

13. van der Waals Forces
Electrons travel around the nucleus inconsistently.
This leads to temporary positive or negative areas.
When molecules come close together, these temporary positive and negative areas are attracted to each other
This causes molecules to be attracted to each other.
This attraction is known as van der Waals forces.
In water, this causes cohesion, which is the reason water beads together.