Basic Chemistry What you may or may Not have learned in 8 th grade science…

Atomic Structure Within the nucleus of the atom: Protons - +1 charge Neutron - 0 charge Outside the nucleus Electrons - -1charge

Where are these Atoms Periodic Table of Elements 96% of life’s elements are HONC – 99% = CHNOPS

Close look at elements Atomic Weight = The mass of the nucleus of the atom Atomic Number = The number of protons

How to Draw Out Electron Shells

More about elements  Isotopes  Have more neutrons HOWEVER behave the same as the original because the protons and neutrons still balance each other out  Ions  Have one extra or one less electron  Carbon 13 or Carbon 14 (which is radioactive and used in research)  Molecules vs. Compounds  2H + O H 2 O All are molecules 1 molecule of water or a compound Compound – two or more elements bonded together products reactants

Bonding COVALENT BONDS – sharing of electrons between atoms Non polar – electrons are equally shared Polar – electrons are not equally shared (electrons get pulled towards a higher electronegative molecule

Water is polar covalent bonding

More Bonds  Ionic Bonds – one atom pulls the electron away from the other atom  Opposite charges attract each other

Perhaps one of you gentlemen would mind telling me just what is outside the window that you find so attractive...?"

Bonds Between Compounds Dipole - Dipole – forms weak bonds to make a new compound (while keeping the original intact) involves attaching the positve end to the negative end) Hydrogen Bonds – hydrogen covalently bonded to one atom will also be attracted to one another - 20x weaker then covalent bonds

Water Chemistry We just saw that Hydrogen Bonding effects water… It is a polar molecule - a positive and negative end … Water is cohesive – H bonds holding it together – that’s how water gets up a plant Water is adhesive – water will cling to other substances as well (meniscus) Surface Tension – at the interface between water and air is a highly ordered arrangement of molecules