Matter and the Atom Chemistry 11

Chemistry Bulletin  The aircraft should have received 20088L  This would be determined by:  Fuel required – 22300kg  Fuel on board – 7682L  Conversion factor – 1.77lbs/L  Conversion factor – 0.803kg/L

Chemsitry Bulletin  Fuel required for flight 22300kg /.803kg/L = 27770L  Fuel on board 7682L  Additional fuel needed 27770L – 7682L = 20088L

Matter and the Atom  The atom is composed of three subatomic particles: ParticleChargeSymbolMass (in g) Radius (in m) Electron1-e-e- 9.02x < Proton1+p+p+ 1.67x neutron0n0n0 1.67x

Atomic Mass Unit (u)  As the subatomic particles are very small, rather than use grams to express their mass, we often use the Atomic Mass Unit (u)  1u = 1.66x g Proton mass = 1u Neutron mass = 1u Electron mass = 0u

Atomic Nucleus  Atom described using: X – atomic symbol A – atomic mass number Z – atomic number  Number of protons and electrons = Z  Number of neutrons = A - Z

Ions  If presented with an ion (charged atom) the number of electrons can be determined using the charge and atomic number. O 2- Oxygen’s atomic number is 8 meaning an uncharged atom will have 8 protons and electrons An oxygen ion (O 2- ) has two additional negative charges (electrons) so it has 10 electrons and 8 protons +8 + (-10) = -2

Practice Problems  Page 9 Question 4  Page 11 Questions 1-6  Page 14 Question 5