1. Atoms, Structures, and Properties

• The Scientific Approach to Knowledge

  • science: observation of the physical world

  • scientific law: amount of related observation to create a generalization

  • hypothesis: explanation of observations

  • scientific theory: explains underlying reasons for observations and laws

  • experiments: controlled procedures designed to produce new observations

• Modern Atomic Theory and the Laws That Led to It

  • Law of Conservation of Mass: in a chemical reaction, matter is neither created nor destroyed

  • Law of Definite Proportions (constant composition): All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements

  • Law of Multiple Proportions: When 2 elements form 2 different compounds, the masses of element B that combine with 1 g of element A can be expressed as a ratio of small whole numbers

  • Dalton’s Atomic Theory:

    • elements are composed of tiny, indestructible particles called atoms

    • all atoms of an element have the same mass and other properties

    • atoms combine in simple, whole number ratios to form compounds

    • atoms of one element can’t change into atoms of another element, they simply bind together with other atoms

• The Structure of the Atom

  • Thomson’s Plum-Pudding Model

    • negatively charged electrons were small particles held within a positively charged sphere

  • Rutherford’s Nuclear Model

    • most of atom’s mass and all of its positive charge are in the nucleus

    • most of the atom is made of empty space, with electrons dispersed

    • there are negatively charged electrons outside the nucleus and positively charged particles (protons) within the nucleus, making the atom neutrally charged

  • Chadwick → discovered neutrons in the nucleus

• Subatomic Particles: Protons, Neutrons, and Electrons

  • protons and neutrons have nearly identical masses

  • protons and electrons have electrical charges

  • elements are defined by the amount of protons

• Atomic Mass: The Average Mass of an Element’s Atoms

  • Atomic Mass: average mass of an elements isotopes

• Elements and Isotopes

  • sum of the fractions of the isotopes times the mass of each isotope

  • masses of atoms and their abundance are measures using mass spectrometry

• Intensive vs Extensive Properties

  • Intensive: used to identify substances based on type (ex: density)

  • Extensive: depends on the amount of the substance (ex: mass)

• Chemical vs. Physical Properties

  • Physical Properties: property that a substance displays w/o changing its composition

    • order, taste, color, appearance, melting point, boiling point and density

  • Chemical Properties: property that a substance displays only by changing its composition via a chemical change

    • corrosiveness, flammability, acidity, toxicity

• Conservation Laws: Mass and Energy

  • Energy: capacity to do work

  • Law of Conservation of Energy: energy is neither created nor destroyed

2. Measurement, Problem Solving, and the Mole Concept

• The Metric System and SI Units

  • prefix multiplier

    • Giga: 10⁹

    • Mega: 10⁶

    • Kilo: 10³

    • Deci: 10^-1

    • Centi: 10^-2

    • Milli: 10^-3

    • Micro: 10^-6

    • Nano: 10^-9

    • Pico: 10^-12

  • standard units:

    • length → meters

    • mass → kg

    • time → sec

    • temp → K

    • amount → mol

    • electric current → A

• Scientific Notation

• Significant Figures

• Consistency vs. Precision

• Density

• Energy and Its Units

• Converting between Units

• Problem-Solving Strategies

• Solving Problems Involving Equations

• The Mole Concept

  • 1 mol = 6.022 × 10²³ particles

3. Chemical Bonds, Formulas, and Names

• Types of Chemical Bonds

  • Ionic Bonds: form between metal and nonmetals, involve the transfer of electrons

    • metals lose electron to nonmetals, become cation and anion

    • form compound with a lattice (regular 3-D array) structure

  • Covalent Bonds: between two or more nonmetals, involve the sharing of electrons

    • form molecular compounds

• Representing Compounds: Chemical Formulas and Molecular Models

  • Empirical Formula: gives the relative number of atoms of each element in a compound

  • Molecular Formula: actual number of atoms of each element in a molecule of a compound

  • Structural Formula: uses lines to represent covalent bonds and shows how atoms in a molecule bond to each other

    • single bond: weaker, longer

    • double bond: stronger, shorter

  • Ball-and-Stick Model

• The Lewis Model:

  • Representing Valence Electrons with Dots

  • The Octet Rule

• Ionic Bonding: The Lewis Model and Lattice Energies

• Molecular Compounds: Formulas and Names

• Formula Mass and the Mole Concept for Compounds

• Composition of Compounds

• Determining a Chemical Formula from Experimental Data