2-1 The Nature of Matter

Pages 34 – 39

(2 Goals)

Goal 1

Review basic chemistry concepts

• Atoms– Basic unit of matter– Made up of 3 subatomic particles– Atoms have a net neutral charge

– Proton• Large particle• + charge

– Neutron• Large particle• No charge

– Electron• Small particle• - charge

• Element– Specific # of protons– Unique properties

• Reading Periodic table– Atomic # number of

protons or electrons

– Mass number total number of protons + neutrons

– Right column number of electrons, bottom number indicates valence electrons

6 24

carbon12

35 28

187

bromine80

• Isotopes– Same number of protons– Different number of neutrons– Chemical properties remain same– Mass number changes– Mass changes

• Example – One atom of “Carbon”

• 6 protons• 6 neutrons• Atomic mass ~ 12

– One isotope of “Carbon – 14” • 6 protons• 8 neutrons !!!• Atomic mass ~ 14

• How many neutrons are in the following isotopes?– Nitrogen -15– Sulfur – 35– Calcium – 45– Iodine - 131

• Radioactive isotopes– Nuclei fall apart– Unstable

• Radioactive tracers– Short-lived– Medicine

• Tumor location• Treatment• Drug path

PD-gov NIH

Goal 2

Review covalent and ionic bonding and compounds

• Compound

– Two or more different elements chemically combined

O2 H2

H2O HNO3 CO2

C6H12O6

• Covalent bonding– Forms covalent compounds– Molecules– Share electrons

– Memorize the following molecules and their chemical formulas:

• Water H2O

• Ammonia NH3

• Methane CH4

• Carbon dioxide CO2

• Ionic bonding– Forms ionic compounds– Transfer of electrons– + and – charges attract each other

– Memorize the following ions and their chemical formulas:

• Sodium chloride NaCl• Potassium chloride KCl

• Calcium carbonate CaCO3

• Magnesium sulfate MgSO4