Chemistry Notes Lindstrom 2010

Why Study Chemistry in Biology?

Banana Cell with Starch Granules

The Size of an Atom

I. Matter 1.Humans and organisms and everything around them are made of MATTER 2.Matter is made up of chemical ELEMENTS 3.Pure substances that cannot be broken down into SIMPLER substances. 4.About 25 elements are essential to life…. 96% of your body is made up of CARBON, Oxygen, HYDROGEN, and Nitrogen.

I. Matter 5.All elements in the same column GROUP have the same # of VALENCE ELECTRONS 6. All elements in the same row PERIOD have the same # of ORBITALS

1. 3 Parts: Location of particles: protons + neutrons = nucleus Location of particles: protons + neutrons = nucleus electrons = rotate around nucleus electrons = rotate around nucleus Protons + Neutrons 0 Electrons - III. ATOMS

2.Atomic # = # of protons 3.# protons = # electrons 4.Atomic Mass = (#) of protons + (#) of neutrons

III. ATOMS 5. If you change the number of protons, number of protons, you change the you change the element name. element name.

II. Compounds 1. Define: groups of two or more elements that are bonded together 2. ex: H 2 O, CO 2, NaCl 3.Compound properties are different from individual elements 4.Covalent compounds happen when the atoms share the electrons 5.Ionic compounds happen when electrons are donated from one atom to another

1.Different forms of the same element, have the same # of protons, but different # of neutrons IV. ISOTOPES

2. Some can be radioactive!! 3. Useful for: * Treating cancer, bone imaging- 99Tcm * Fuel/energy- nuclear reactors * Dating fossils * Irradiating food IV. ISOTOPES

4. Electrons belongs to certain energy levels 1 st orbital- 2 ELECTRONS 2 nd orbital- 8 ELECTRONS

V. Bonding 1.Atoms want to fill their outer energy levels to be HAPPY 2.In order to do this, they will meet up with other atoms and either share or exchange electrons This is a covalent bond. Electrons are SHARED.

1. Atoms EXCHANGE electrons, becoming POSITIVELY or NEGATIVELY charged 2. This attraction brings them TOGETHER 3. Ex: Na+ and Cl- VI. IONIC BONDING

VII. COVALENT BONDING 1. Atoms SHARE electrons so that both atoms fill their outer energy level 2. Elements can only use electrons from their OUTER ORBITAL to bond with other elements 3. Carbon can form FOUR (4) covalent bonds

PHYSICAL CHANGE Describe: Describe: A physical change does not produce a new substance. Changes in phase (melting, freezing, vaporization, condensation, sublimation) are physical changes. A physical change does not produce a new substance. Changes in phase (melting, freezing, vaporization, condensation, sublimation) are physical changes. 3 examples: 3 examples: crushing a can crushing a can melting an ice cube melting an ice cube breaking a glass bottle breaking a glass bottle

CHEMICAL CHANGE Describe Describe Chemical changes take place on the molecular level. A chemical change produces a new substance. Chemical changes take place on the molecular level. A chemical change produces a new substance examples: combustion (burning) combustion (burning) cooking an egg cooking an egg rusting of an iron pan rusting of an iron pan

VIII. CHEMICAL REACTIONS 1.Define reactants: the ingredients into a chemical reaction 2.Define products: the results of a chemical reaction H 2 + O --  H 2 O