chapter 2.pdf

The Nature of Atoms Define an element based on its composition: something that can’t be broken down Atomic number: number of protons Atomic mass: mass of atom Relationship Between Atomic Structure and Chemical Properties Electrons: subatomic particles with a negative charge that orbit th...

The Nature of Atoms Define an element based on its composition: something that can’t be broken down Atomic number: number of protons Atomic mass: mass of atom Relationship Between Atomic Structure and Chemical Properties Electrons: subatomic particles with a negative charge that orbit the nucleus of an atom. Cations: A positively charged ion. Anions: A negatively charged ion. Isotopes: Different forms of the same element with the same number of protons but different numbers of neutrons. Radioactive isotopes: An isotope that is unstable and undergoes radioactive decay, releasing energy. Electrons and Atomic Chemical Behavior Explain where electrons are found in an atom and how they affect the atom's chemical behavior outside orbiting the nucleus can be spherical or orbital Elements Found in Living Systems Relate atomic structure to the periodic table of elements: Valence electrons: An electron in the outermost energy level of an atom. Octet rule: Rule to describe patterns of chemical bonding in main group elements that require a total of eight electrons to complete their outer electron shell. Energy levels: List the important elements found in living systems: 1. Oxagen 2. hydrogen 3. carbon 4. nitrogen 5. 6. 7. 8. 9.  10. 11. 12. The Nature of Chemical Bonds Molecule: Chemical bond: Ionic bond: Covalent bond: 1. Predict which elements are likely to form ions: 2. Explain how molecules are formed from atoms joined by covalent bonds: 3. Contrast polar and nonpolar covalent bonds: a. Polar: b. Non-polar: Chemical reaction: Chemical reactions involve the formation or breaking of chemical bonds  Reactant: Reactants = original molecules Product: Products = molecules resulting from reaction Factors Influencing Chemical Reactions Water: A Vital Compound Relate how the structure of water leads to hydrogen bonds: Hydrogen bonds: Water's Cohesive and Adhesive Properties Cohesion: allows molecules to be attracted to each other Surface tension: surface of a liquid Adhesion: the attraction between different substances Properties of Water Illustrate how hydrogen bonding affects the properties of water: High specific heat: Heat of vaporization: Density: Solubility of polar molecules and ions: Non-polar molecules: Water’s Relevance to Living Systems Explain the relevance of water’s unusual properties for living systems: Dissociation Products of Water Acids and Bases Acids:  Base: pH scale: Relate changes in pH to changes in [H+]: Buffers: