Presentation on theme: "The Ancient Greeks used to believe that everything was made up of very small particles. I did some experiments in 1808 that proved this and called these."— Presentation transcript:
The Ancient Greeks used to believe that everything was made up of very small particles. I did some experiments in 1808 that proved this and called these particles ATOMS: Dalton
2. Elements-substances that consist of just one type of atom; they cannot be broken down to other substances 1. Atom-the basic unit of all matter; the smallest unit of matter that retains the properties of an element 3. Molecule-substance containing 2 or more atoms 4. Compound-substance containing 2 or more elements
Is brass an element? What about: Oxygen O 2 Water H 2 0 Helium He Is brass a molecule? Is brass a compound?
The structure of the atom ELECTRON negative, orbits outside the nucleus in the ELECTRON CLOUD PROTON positive, also in nucleus NEUTRON neutral, located in the NUCLEUS (center of atom)
+++++ positive and negative are opposites they cancel each other out net charge = zero
+++++ In an atom, protons ( ) are in the center and electrons ( ) are on the outside + only electrons ( ) can be added or taken away
+ + + + + This is an atom with 5 electrons and 5 protons The atom is neutral 5 (-) and 5 (+) = zero charge (neutral)
Hydrogen atoms are very reactive…. Helium is not. Which do you think the Hindenburg was filled with? Atoms want 8 electrons in the outermost shell. If atoms have less than 8 then they react with other atoms to gain or lose electrons.
Atoms will react to get 8 electrons in the outer shell. This can cause the atoms to bond with each other. FK IONIC bond – bond formed when electrons are lost from one atom and gained by another.
Monomer-Nucleotide Stores and transmits genetic information Two types Deoxyribonucleic acid – DNA Ribonucleic acid - RNA Nucleic Acids
Lipids Used to store energy One gram of fat contains over twice the energy of one gram of carbohydrate Important categories Fats, Oils, Waxes Steroids Phospholipids Structure Glycerol molecule + 3 fatty acids
Cohesion and Adhesion Hydrogen bonds give water its cohesive and adhesive properties. Cohesion-water is attracted to other water Adhesion-water attracted to other materials
Surface tension Cohesion of water molecules at the surface of a body of water
Capillary Action Water climbs up capillaries (like straws or plant stems) The water molecules are attracted to the capillary molecules. When one water molecule moves closer to the capillary molecules the other water molecules (which are cohesively attracted to that water molecule) also move up into the capillary. Capillary action is limited by gravity and the size of the capillary. The thinner the capillary the higher up capillary action will pull the water
High Specific Heat Water does not change temperature easily This is why coastal areas have a more constant temperature. This is also why life forms have a more constant temperature.
Solutions Solutions are mixtures where the solute is evenly distributed in the solvent (completely dissolved) Water is a very good solvent
Water and Life Water is essential for life. Most animals and plants contain more than 60% water by volume. Without water life would probably never have developed on our planet.