Syllabus:

• History of an atom

• Structure of an atom

• Bohr models

• Organization of the periodic table

• Lewis dot structure (ionic and covalent bonding)

• Electronegativity

• Physical and chemical change

• Types of reactions

• Balancing chemical equations

• Photosynthesis

• Cellular respiration

HISTORY OF AN ATOM

• Democritus thought matter could not be created nor destroyed

• Aristotle modified an earlier theory that matter was made of four “elements”: earth, fire, water, and air. He was incorrect.

• John Dalton came up with several ideas including all matter is made up of atoms

• JJ Thompson discovered the electron

• Ernest Rutherford conducted the gold foil experiment, which led to the discovery of the atomic nucleus

• Chadwick discovered the neutron, which further contributed to our understanding of atomic structure

STRUCTURE OF AN ATOM

• The atom consists of a central nucleus, made up of protons and neutrons, surrounded by a cloud of electrons that occupy specific energy levels

• Protons have a positive charge, neutrons have a neutral charge, and electrons have a negative charge

• 2-8-18-32-32-18-8 (number of electrons on each shell)

  

• Atomic number: number of protons

• Atomic number: number of electrons

• Group: number of valence electrons

• Period: number of shells

• Mass number: number of protons and number of neutrons

• An iscotope is when the protons and neutrons of an atom are not equal

BOHR MODEL

ORGANIZATION OF THE PERIODIC TABLE

• Arranged in order of increasing atomic number

• 7 periods

• 18 groups

• 9 families

  • Alkali metals (shiny, soft, most reactive)

  • Alkaline earth metals (second most reactive family)

  • Transition metals (appear as metals, they are malleable and ductile and they conduct heat and electricity)

  • Post-transition metal (soft or brittle, with poor mechanical strength, and melting points lower than the transition metals)

  • Metalloids (properties of both metals and non-metals)

  • Other nonmetals (good insulators of heat and electricity)

  • Noble gases (rarely react with other elements)

  • Lanthanoids (produce a lot of energy when reacting with hydrogen, high boiling points and high melting points)

  • Actinoids (highly radioactive, unstable nucleus, metals tarnish in air)

• Pnictogen, Chalcogens, Halogens (15, 16, 17 group on periodic table)

• Boron Group or Earth Metals: Group 13 - three valence electrons

• Carbon Group or Tetrels: Group 14 - four valence electrons

• Nitrogen Group or Pnictogens: Group 15 - five valence electrons

• Oxygen Group or Chalcogens: Group 16 - six valence electrons

LEWIS DOT STRUCTURE

• Covalent bond: sharing of electrons

  • nonmetal x nonmetal

• Ionic bond: transfer of electrons

  • metal x nonmetal

    

ELECTRONEGATIVITY

PHYSICAL AND CHEMICAL CHANGE

• Physical change:

  • affect form but not chemical composition

  • reversible

  • no new substances are formed

  • a change in the matter identity

• Chemical change:

  • one or more substances are formed

  • can’t be reversed

  • change in color (sometimes)

  • formation of gas

  • change in odor

  • change in temperature

  • produces light

TYPES OF REACTIONS

• Synthesis

• Decomposition

• Single-replacement

• Double-replacement

• Combustion

• Endothermic: when energy is taken in from the surroundings

  • usually feels cold

• Exothermic: when energy is transferred to the surroundings

  • usually feels hot

PHOTOSYNTHESIS

• 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

• Reactants: Carbon dioxide, water, energy from sunlight

• Products: Glucose, oxygen

• Most photosynthetic cells found in the leaves

• Light-dependent reaction: 12 H₂O + 12 NADP⁺ + 18 ADP + 18 P_i + light —> 6 O₂ + 12 NADPH + 18 ATP

• Calvin cycle: 3 CO₂ + 6 NADPH + 5 H₂O + 9 ATP —> G3P + 2 H⁺ + 6 NADP⁺ + 9 ADP + 8 Pi

• Light-dependent reaction occurs in the chloroplast: thylakoid and stroma

• Calvin cycle occurs in the stroma of the chloroplast

CELLULAR RESPIRATION

• C₆H₁₂O₆ + 6O₂--> 6CO₂ + 6H₂O + ATP

• Reactants: Glucose, oxygen

• Products: Carbon dioxide, water, energy

• Glycolysis: Glucose —> Pyruvic acid + 2 ATP

• Krebs Cycle: Pyruvic acid —> CO_{2 +} Chemical energy

• Electron Transport System (ETS): O₂ + Chemical energy —> H₂O + 36 ATP

• Glycolysis occurs in the mitochondria: matrix and cytoplasm

• Krebs Cycle occurs in the matrix

• ETS occurs in the cristae of mitochondria