Chemistry Worksheets
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1
2
3Chemistry
Chapter 2
Chapter Outline
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Atoms
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Ions
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Chemical Bonds
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pH scale
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Water
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Carbohydrates
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Lipids
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Proteins
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Nucleic Acids – DNA and RNA
Atoms and Ions
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All matter is formed of Atoms.
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Each atom has protons and neutrons in nucleus.
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Protons are positively charged particles.
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Neutrons are neutral particles.
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Nucleus is surrounded by a cloud of electrons.
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Electrons are negatively charged particles.
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Ions have different # of protons and electrons.
Human Body and Elements
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Human body has 24 elements
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Elements have only 1 type of atoms.
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Major Elements – 99.3%
H, O, C and N
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Mineral Elements – 0.7%
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Trace Elements – less than 0.01%
Importance of # of atomic particles
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Atomic Number: # of protons determine the element; 1 = H, 6 = C, 7 = N and so on.
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Mass Number is equal to # of protons + # of neutrons
12
14
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# of neutrons determine the isotope; C
is the most common carbon and has 6 p + 6 n but C
has 6 p + 8 n and is radioactive.
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# of electrons in outer shell determines chemical behavior of a molecule. # of covalent bonds made by H = 1, O = 2, N = 3, C =
4 and P = 5
Chemical Bonds
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Atoms interact to form molecules. 3 basic type of interactions between atoms are:
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Covalent bonds
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Ionic bonds
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Hydrogen bonds
Covalent Bonds
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Covalent bonds: Atoms form share electron pair to form covalent bond.
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Unequal sharing of electrons result in Polar molecules. Equal sharing of electrons result in non-polar molecules.
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Very strong bonds.
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Non-polar molecule Methane = CH
4
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Polar molecules: water = H
O, and ammonia = NH
2
3
Ionic Bonds
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Atoms change into ions by complete transfer of electron/s.
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A positive ion and a negative ion attract each other and form ionic bond.
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