CHEMICAL BONDING,

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CHEMICAL BONDING, CHEMICAL FORMULAE
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Review of Atomic Structure
The atom is a building block of matter Atoms
consist of Protons (positive electrical
charge) Neutrons (electrically neutral no
charge) Electrons (negative electrical
charge) Nucleus (protons and neutrons
positive) Electron shells (where electrons move
rapidly around the nucleus)
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Composition
of protons atomic number of the element
of protons is always the same as the of
electrons of protons of neutrons atomic
mass of the element
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Electrons orbit in shells
1st shell can fit 2 electrons
2nd and 3rd shells can fit 8 electrons
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Example
Draw the following electron shells
Cl
Al
VALENCE
electrons is,
the outer
ring
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Dot Diagrams
Write the element symbol Draw dots one for
each valence electron around the symbol
valence electrons group Dots are spread
around all 4 sides, not paired until all sides
have at least 1 dot Does not matter which side
dots are placed
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Examples
Li
CL
C
Mg
Ne
O
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Complete circle and dot diagrams for the first
20 elements on the periodic table (handout)
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Atoms are stable when their outer shells are
full Atoms gain or lose electrons depending on
which is easier to become stable Eg. Easier for
Na to lose 1 electron than to gain 7
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Elements and Compounds
Element All the atoms are exactly the same Eg.
Oxygen, gold, silver, etc.
Compound Substances that are made up of 2 or
more different atoms bound together Eg. Sugar
carbon, hydrogen and oxygen
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Chemical Bonds
The Carbon, Hydrogen and Oxygen in sugar are
chemically bonded.
Chemical bonds can form between the same atom or
different types of atoms. Opposites attract
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COVALENT BOND
When a non metal reacts with a non
metal Both atoms share the electrons
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Examples
Hydrogen Hydrogen
Hydrogen Chlorine
Carbon Oxygen
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Hydrogen Hydrogen Hydrogen
Chlorine Carbon Oxygen
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IONIC BOND
When a metal reacts with a non
metal Involves a complete transfer of
electrons Produces ions (charged particles)
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Examples
Potassium Flourine
Sodium Chlorine
Aluminium Chlorine
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Potassium Flourine Sodium
Chlorine Aluminium Chlorine
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Complete handout for practice with ionic and
covalent bonding!
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LAB SAFETY!!!
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Safety Rules
Follow instructions Push in chairs and keep
walkways clear Keep books and papers away from
heating equipment and chemicals Inform teacher
immediately of any spills, broken equipment, cuts
or burns Point the mouth of the test tube away
from you and other students No food or drink in
the lab Clean up and wash hands thoroughly after
an experiment
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Clothing
WEAR Safety goggles Lab coat Closed toe
shoes Long hair tied back in a pony tail Do
NOT wear Sandals Loose or baggy clothing
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Measuring
Measure from eye level Miniscus Balance
scales to zero before use
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Recording Observations
Construct a table with clear headings of what is
being measured Remember to include all
units! Be consistent