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General Chemistry: Basic Concepts and Atomic Structure

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Termini in questo insieme (27)

  • SI Base Units

    Length: meter (m), Mass: kilogram (kg), Time: second (s), Temperature: kelvin (K), Amount of substance: mole (mol), Electric current: ampere (A), Luminous intensity: candela (cd).

  • Metric Prefixes

    Common prefixes include Giga (109), Mega (106), Kilo (103), Deci (10-1), Centi (10-2), Milli (10-3), Micro (10-6), Nano (10-9), Pico (10-12).

  • Significant Figures

    Digits in a measured number including all certain digits plus one uncertain digit. Leading zeros are not significant; trailing zeros are significant if after a decimal point.

  • Rules for Significant Figures in Calculations

    Multiplication/Division: result has as many significant figures as the least precise factor.
    Addition/Subtraction: result has as many decimal places as the least precise measurement.

  • Exact Numbers

    Numbers that are counted or defined exactly, such as 12 inches = 1 foot, have infinite significant figures.

  • Dimensional Analysis

    A method to convert units using conversion factors to ensure units cancel properly and the correct units remain.

  • Density

    Density is mass per unit volume, typically g/cm3 for solids/liquids and g/L for gases.

  • States of Matter

    Solids: fixed shape and volume.
    Liquids: fixed volume, no fixed shape.
    Gases: no fixed volume or shape, easily compressed.

  • Pure Substances

    Cannot be separated by physical means.
    Elements: one type of atom.
    Compounds: two or more elements chemically combined.

  • Mixtures

    Heterogeneous: physically distinct parts.
    Homogeneous: uniform composition throughout.

  • Scientific Method Terms

    Hypothesis: tentative explanation.
    Experiment: controlled observation.
    Theory: tested explanation.
    Law: concise statement or equation.

  • Dalton's Atomic Theory

    Atoms of an element are identical.
    Elements composed of atoms.
    Compounds formed by atoms in whole number ratios.
    Atoms rearranged in reactions.

  • Law of Conservation of Mass

    Matter is neither created nor destroyed in a chemical reaction; total mass remains constant.

  • Law of Definite Proportions

    A compound always contains the same elements in the same fixed proportion by mass.

  • Law of Multiple Proportions

    When two elements form more than one compound, the masses of one element combine with a fixed mass of the other in ratios of small whole numbers.

  • Structure of the Atom

    Atom consists of a nucleus (protons and neutrons) and electrons in the surrounding space.

  • Rutherford's Nuclear Theory

    Most mass and positive charge in nucleus.
    Atom mostly empty space.
    Number of electrons equals number of protons.

  • Atomic Number

    Number of protons in the nucleus; defines the element.

  • Mass Number

    Total number of protons and neutrons in the nucleus.

  • Isotopes

    Atoms of the same element with the same atomic number but different mass numbers due to varying neutrons.

  • Atomic Mass Unit (amu)

    One twelfth the mass of a carbon-12 atom; protons and neutrons have ~1 amu; electrons ~0 amu.

  • Average Atomic Mass

    Weighted average of the atomic masses of an element's isotopes based on their natural abundance.

  • Periodic Table Arrangement

    Elements arranged by increasing atomic number with groups (columns) and periods (rows) showing similar properties.

  • Groups/Families

    Examples: Alkali metals (Group IA), Alkaline earth metals (IIA), Halogens (VIIA), Noble gases (VIIIA).

  • Ions and the Periodic Table

    Main group metals tend to lose electrons forming cations; nonmetals tend to gain electrons forming anions.

  • Mole Concept

    A mole contains Avogadro's number (\(6.022 \times 10^{23}\)) of particles.

  • Molar Mass

    Mass of one mole of a substance, numerically equal to the average atomic mass in grams.