Concept of Matter and Energy Chemistry of Life Concept of Matter and Energy

Matter (has mass and takes up space) Element: building block that can’t be broken *major elements in body – O, C, H, and N Atom: smallest unit of matter Molecule: when 2 or more atoms share electrons Ion: when an atom gives up/gains electrons and is charged

Parts of an atom: proton, neutrons, electrons

Using the Periodic Table # protons = atomic number #neutrons = mass number (rounded) – atomic # # electrons = # protons

Periodic Table Groups- run vertically Periods- run horizontally

Chemical Bonds Valence Shell: number of electrons in the outer shell Chemically stable: atom with 8 electrons in valence shell Ionic Bonds (strong): Opposites attract—force of attraction between ions of opposite charges Electrolyte: ionic compound that breaks apart into cations(+) (/anions (-) when dissolved *most ionic bonds are found in bones/teeth Covalent bonds (weak): When atoms share electrons *most found in the body’s organs

Isotopes Isotopes: elements that have same number of protons, but different number of neutrons Radioactive isotopes used as tracers or markers in the body Barium: viewing digestinal tract Iodine: used in testing the thyroid Strontium: used to identify bone cancer

Types of Reactions Synthesis: put together A + B AB Decomposition: split apart AB A + B Exchange: AB + CD AD + BC Reversible: AB A + B

Energy Types Kinetic: energy of motion Potential: energy due to position / stored energy Types: Thermal: heat (muscular) Chemical: (digestion, chemical reactions) Electrical: (nerve signals) Radiant: light waves from sun (integumentary, muscular) Mechical: movement

pH (potential hydrogen)