Basic Chemistry Basic Chemistry & & Chemical BondsChemical Bonds
Subatomic ParticlesSubatomic Particles
Proton (+)Electron (-)Neutron (n)Nucleus of an atom contains protons and neutronsElectrons orbit the nucleus
Periodic TablePeriodic Table
Used to organize elements using their subatomic particle information
ElementsElements
Pure substance of only one atom
CompoundCompound
2 or more elements combined
Some other examples?
Sodium chloride (NaCl)… salt
Covalent BondsCovalent Bonds
Electrons are shared
Example: water (H2O)
Ionic BondsIonic Bonds
Electrons are exchanged
Example: sodium chloride (NaCl) or salt
Hydrogen BondsHydrogen Bonds
Weak and break easily
Polar MoleculesPolar Molecules1 part (+) 1 part (-)soluble in other polar compounds, and insoluble in non-polar compounds.
Example: H2O
Non-polar MoleculesNon-polar Molecules
The charges all cancel out each other
Example: CO2
Acids, Bases, and pHAcids, Bases, and pHBiology
pH ScalepH ScaleMeasurement system that indicates the
concentration of H+ ions in a solutionRuns from 0 to 14Compares acidity/basicity
◦A solution that has equal numbers of hydrogen and hydroxide ions is neutral and is pH 7 (pure water)
Each increase in a number on the pH scale = 10X higher pH◦Example: pH of 4 is 100X lower (more acidic)
than pH of 6
AcidsAcids
Any compound that forms H+ ions when dissolved in water
pH of less than 7The closer to 1, the stronger the acid
Example: Vinegar
BasesBases
Any substance that forms OH- (hydroxide) ions when dissolved in water
pH greater than 7The closer to 14, the stronger the base
Example: Bleach
Why is pH important?Why is pH important?
Organisms have an internal pH that must remain fairly stable for chemical reactions to occur optimally, thus…
Controlling pH is essential for homeostasisBuffers are weak acids or bases that can
react with strong acids or bases to prevent sharp, sudden changes in pH