General Chemistry 2011

 The science of matter and the reactions caused when different kinds of matter interact. What people use chemistry to do their jobs?

 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.

 The smallest unit of matter How small is small? 1 Atom of Helium Diameter = 50 picometers Mass = 1.67 x kilograms This is a carbon atom. Atoms most common in living organisms: carbon nitrogen hydrogen oxygen

Name: Description: Favorite Activity: Name: Description: Favorite Activity: Name: Description: Favorite Activity:

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 (-) 1 st Cloud: 2 electrons 2 nd Cloud: 8 electrons 3 rd Cloud: 8 electrons

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: ___________________

The number of protons an atom has. This number never changes! Can be found on the periodic table

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 Tabclass website Open/Print the Atomic Structure Practice Worksheet Complete the worksheet at home or during study hall and bring it to Mrs. Coleman to check!

1. Draw the Nucleus 2. Add protons (+) and neutrons (o) into the nucleus 3. Draw at least one electron level. 4. Add electrons remembering the number each level can hold; you may need to add more electron levels 1 st : 2 electrons 2 nd : 8 electrons 3 rd : 8 electrons

A chart of all elements known to man. Arranged in rows and columns. In order of atomic number.

 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)

ElementNumber of Protons Number of Neutrons Number of Electrons 1 st Energy Level Electrons 2 nd Energy Level Electrons 3 rd Energy Level Electrons Carbon Chlorine Helium Hydrogen Lithium Magnesium Neon Nitrogen Oxygen Phosphorous Sodium Sulfer

Why 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. AtomProtonsNeutronsElectrons1 st Energy Level 2 nd Energy Level 3 rd 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.

COVALENT 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

Ion: 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… HeliumHydrogen SodiumOxygen Chlorine

SodiumChlorine

MagnesiumOxygen

 Gains an electron? The atom becomes more negative (negative ion)  Loses an electron? The atom becomes more positive (positive ion)

Molecule: Two or more atoms that are covalently bonded (sharing electrons).

HydrogenFluorine

Oxygen

HydrogenOxygenHydrogen

ElementSymbolDot DiagramStable? Unstable? Gain or Lose? How many? Hydrogen Helium Lithium Carbon Aluminum Sulfur Chlorine Argon Chemical Bonding

1. LiCl Type of Bond: Explanation: