Download Section 1 Atoms, Elements, and Compounds

Chapter 6 Study Guide
Section 1 Atoms, Elements, and Compounds
Atomic Theory
 What is it? How came up with it? Why couldn’t he prove it?
Atomic Structure
 Nucleus- center of atom, majority of mass located here
 Protons- positively charged particles in nucleus
 Neutrons- neutral charged particle in the nucleus
 Electrons- negatively charged particles that orbit the nucleus. Very small.
o Energy Levels- 2 electrons in first energy level. 8 in every level after that
o Valence- Outermost, used in chemical bonds
What makes an atom neutral?
Elements
 What is an element and what are some common elements?
 Atomic Number- Used to identify elements, describes number of protons.
 Mass Number- Mass # = Protons + Neutrons
 Isotopes- same number of protons, different number of neutrons.
 Ions- An atom/element with an overall net charge (+/-). Different number of electrons than protons.
Compounds
 Combination of two or more different elements through a chemical bond.
 Know some common compounds (water, carbon dioxide, glucose, etc…)
 Molecules
o A type of compound held together by only covalent bonds. Can be composed of only one
element (oxygen gas O2)
Chemical Interactions/Bonds
 Opposite charges attract
 Covalent bond
 Sharing of electrons
 Very strong bond
 Polar- unequal sharing of electrons. Creates dipoles. Example: water
 Non polar-equal sharing. Example: methane
 Ionic
 One atom obtains (steals) one or more electrons from another atom.
 Creates ions.
 Charges between ions create the bond.
 Strong force.
 Example: Salt (NaCl)
Section 2: Chemical Reactions
Chemical Reactions
 Atoms are rearranged through the breaking of chemical bonds to form new compounds.
 Indicators: heat, light, change of state.
Chemical Equations
 Reactants  Products
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Conservation of Mass
o Mass is never created or destroyed. Some you will have the same elements on both sides of
an equation.
Balancing
o The number of atoms must be the same on both sides of an equation.
Energy
 The ability to do work
 Can’t be created or destroyed, can only be transferred to different forms.
 Potential
 Stored in chemical bonds
 Created when an object is lifted from the ground
 Kinetic
 Energy of motion
 Activation Energy- amount of energy needed to start a reaction
 Exothermic
 Products have less energy than reactants
 Energy is lost from the system usually in the form of heat or light
 Generally low activation energy
 Endothermic
 Products have more energy than reactants
 Energy is absorbed.
 Generally high activation energy
Enzymes
 Lowers activation energy
 Doesn’t get used up
 Binds substrates
 Speeds up reactions
 Effected by range of tolerance
o Works within a specific temperature and pH range. Amount of substrates can also effect
activity.
 Active site
o Area where substrates bind
o Specific to specific substrates (lock and key example)
Section 3: Water and Solutions
Polarity
 Slight positive and negative charges formed create poles.
 Hydrogen bonding
o A weak interaction between dipoles using hydrogen.
Mixtures
 Homogenous
o Uniform composition. Example: Salt water
 Heterogeneous
o Components do not dissolve, remain intact. Example: salad, rocks in a beaker of water.
 Solute
o The substances that dissolves. Usually a solid, but not always.
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Solvent
o The substance the solute dissolves in. Usually a liquid.
Acids and Bases
 Acid
 Donates a hydrogen ion (H+ )
 pH under 7
 Base
 Accepts a hydrogen ion.
 Usually has a hydroxide group (OH-)
 pH over 7
 Buffers
 Resist change in pH.
Section 4: The Building Blocks of Life
Organic Chemistry
 Study of compounds having carbon (except carbon dioxide and carbon monoxide)
 Properties of carbon (4 bonds, makes covalent bonds)
 Can form chains, branched chains or rings.
Macromolecules
 Composed of smaller molecules bonded together to make large compounds.
 Carbohydrates
o (CH2O)n
o Monosaccharide
o Disaccharides
o Polysaccharide
o Used for energy and building structure in cells
 Lipids
o Also called fats. Made of carbon and hydrogen.
o Triglyceride- solid at room temperature
o Oil- liquid at room temperature
o Saturated Fats
 Only single bonds. Many hydrogen atoms.
o Unsaturated Fats
 Contain double bonds. Less hydrogen atoms. Harder to break down.
 Proteins
o Made of amino acids
o Contain carbon, nitrogen, oxygen, hydrogen, and sulfur
o Contain central carbon atom, amino group (-NH2), carboxyl group (-COOH), and a variable
group (-R)
 Nucleic Acids
o Make up DNA and RNA
o Made of nucleotides