COLEMAN BIOLOGYGeneral Chemistry 2011
Chemistry
The science of matter and the reactions caused when different kinds of matter interact.
What people use chemistry to do their jobs?
Matter
Anything that has mass and volume.
What are some examples of matter that can be found in this classroom?
Does matter exist if we can’t see it?
Give an example of something that is matter but we can’t see it.
Atom
The smallest unit of matter
electron
neutron
proton
How small is small?1 Atom of Helium
Diameter = 50 picometersMass = 1.67 x 10-27
kilograms
This is a carbon atom.
Atoms most common in living organisms:• carbon• nitrogen• hydrogen• oxygen
The Atoms Family
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Subatomic Particles:The parts of the atom
NUCLEUS: CENTER OF THE ATOM
•PROTONS – POSITIVELY CHARGED PARTICLES (+)
•NEUTRONS – PARTICLES WITH NO CHARGE (0)
ELECTRON LEVELS (CLOUDS): INVISIBLE RINGS AROUND THE
NUCLEUS
•ELECTRIONS – NEGATIVELY CHARGED PARTICLES (-)
1st Cloud: 2 electrons2nd Cloud: 8 electrons3rd Cloud: 8 electrons
Particle Charges
Protons have a positive charge (+)Neutrons have no charge (0)Electrons have a negative charge (-)
For the following pairs, decide if the particles will attract or repel.
• proton and electron: ____________________• proton and neutron: ____________________• proton and proton: _____________________• electron and electron: ___________________• neutron and neutron: ___________________
Atomic Structure & The Periodic Table
electron
neutron
proton
ATOMIC NUMBER•The number of protons an atom has.•This number never changes!•Can be found on the periodic table
ATOMIC MASS•Mass of atom is found in the nucleus•Atomic Mass = Protons + Neutrons
If you are having trouble with the parts of the atom, here’s how you can practice…
•Go to class website and click on Chemistry Tab
•Open/Print the Atomic Structure Practice Worksheet
•Complete the worksheet at home or during study hall and bring it to Mrs. Coleman to check!
DRAWING ATOMS
1. Draw the Nucleus2. Add protons (+) and neutrons (o) into the
nucleus3. Draw at least one electron level. 4. Add electrons remembering the number each
level can hold; you may need to add more electron levels
1st: 2 electrons2nd: 8 electrons3rd: 8 electrons
Periodic Table of ElementsA chart of all elements known to man. Arranged in rows and columns. In order of atomic number.
Periodic Table of Elements
Element – a substance made of only one kind of atom Example: Carbon Atoms can combine to make
elemental carbon in the form of coal or diamonds.
Atomic Number – number of protons and electrons; atomic number of an atom never changes
Atomic Mass – number of protons + neutrons (mass of atom is found in the nucleus)
Element Number of Protons
Number of Neutrons
Number of Electrons
1st Energy Level Electrons
2nd Energy Level Electrons
3rd Energy Level Electrons
Carbon
Chlorine
Helium
Hydrogen
Lithium
Magnesium
Neon
Nitrogen
Oxygen
Phosphorous
Sodium
Sulfer
Atomic BondsWhy do atoms bond together?
Atoms bond together to fill up their outermost energy levels which makes
them become stable
Stability:
An atom is stable if its outermost energy level is filled up.
Atom Protons Neutrons Electrons 1st Energy Level
2nd Energy Level
3rd Energy Level
Stable?
Hydrogen
Sodium
Neon
Chlorine
Oxygen
Chemical Bond:
A force that holds two or more atoms together; atoms bond to become stable
Valence Electrons:
The electrons in the outermost energy level only
Dot Diagram:
A diagram that shows the chemical symbol and dots representing only valence electrons
To become stable, atoms can GAIN, LOSE, OR SHARE electrons.
Atomic BondsCOVALENT BOND: •CHEMICAL BOND FORMED BY A SHARING OF ELECTRONS•FORMED WHEN BOTH ATOMS NEED ELECTRONS
IONIC BOND: •CHEMICAL BOND FORMED BY ONE ATOM LOSING ELECTRONS AND ANOTHER ATOM GAINING ELECTRONS
Ionic BondsIon:
An atom that has gained or lost electrons; an atom that has a positive
or negative charge
Draw a Dot Diagram of the following atoms…
Helium Hydrogen
Sodium Oxygen
Chlorine
Dot Diagrams Showing Ionic Bonding
Sodium Chlorine
Dot Diagrams Showing Ionic Bonding
Magnesium Oxygen
What happens to an atom when it…
Gains an electron?
The atom becomes more negative (negative ion)
Loses an electron?
The atom becomes more positive (positive ion)
Covalent BondsMolecule:
Two or more atoms that are covalently bonded (sharing electrons).
Dot Diagrams Showing Covalent Bonding
Hydrogen Fluorine
Dot Diagrams Showing Covalent Bonding
Oxygen Oxygen
Dot Diagrams Showing Covalent Bonding
Hydrogen Oxygen Hydrogen
Element Symbol Dot Diagram
Stable?Unstable?
Gain or Lose? How many?
Hydrogen
Helium
Lithium
Carbon
Aluminum
Sulfur
Chlorine
Argon
Chemical Bonding
1.
Li Cl
Type of Bond:
Explanation: