Chemistry Basics: Data Types and Periodic Table

Qualitative vs. Quantitative Data

• Qualitative data does not involve numbers (e.g., color, size, texture).
• Quantitative data is numerical and based on measurement.

Periodic Table Groups

• Group 1: Alkali Metals
• Group 2: Alkali Earth Metals
• Group 17: Halogens
• Group 18: Noble Gases

Definitions

• Malleability: The ability of a material to be hammered into a thin sheet.
• Conductivity: The ability of a material to transfer heat or electricity well.
• Luster: A science term for shine/brightness
• Precision: How close multiple measurements are to each other.
• Accuracy: How close a measurement is to the true or accepted value.
• Ductility: The ability of a material to be stretched into a thin wire.
• Atom: Means "indivisible"
• Law of Conservation of Mass: Mass/matter is neither created nor destroyed in an ordinary chemical reaction.

Periodic Table

• Group: Elements in the same vertical columns. The group number indicates the number of valence electrons.
• Period: Elements in the same horizontal row.
• Aufbau Principle: Electrons occupy orbitals in order from lowest to highest energy.
• Pauli Exclusion Principle: No two electrons within an atom can have the exact same set of four quantum numbers.
• Hund's Rule: Orbitals in a set are each occupied by one electron before any orbital is doubly occupied.
• SI Units:
  • Time: seconds
  • Length/Distance: meters
  • Mass: kilograms
  • Electric current: amperes
  • Temperature: Kelvin
  • Amount of a substance: moles
  • Luminous intensity: candelas

Scientific Notation

• Example: 82,680,000 = 8.268 x 10⁷

Atoms

• Atoms are electrically neutral due to the equal number of positively charged protons and negatively charged electrons.
• Atoms of the same element have the same number of protons (atomic number).
• Neutrons are calculated by subtracting the atomic number from the mass number.
• Isotopes are atoms of the same element with different numbers of neutrons.

Energy Levels

• Excited State: Highest energy state of an atom.
• Ground State: Lowest energy state of an atom.

Quantum Numbers

• Principle Quantum Number: Indicates the energy level.
• Angular Momentum Quantum Number: Describes the shape of the orbital.
• Magnetic Quantum Number: Indicates the orientation of the orbital.
• Spin Quantum Number: Indicates the spin state of the electron.

Electron Configurations

• Electron configurations describe the arrangement of electrons in an atom.

Mixtures vs. Compounds

• Mixture: A physical combination of substances where individual substances maintain their properties and can be separated by physical methods.
• Compound: A chemical combination of substances where a new substance with different properties results as a result; it cannot be separated by physical methods.

Physical and Chemical Changes

• Physical Change: Change in state, shape, or temperature of matter without a new substance forming.
• Chemical Change: Production of a new substance, unexpected temperature changes when mixing substances, color change.

Dalton's Atomic Theory

• Atoms are indivisible (incorrect - divisible into smaller parts.)
• Atoms of the same element are identical (incorrect - Isotopes exist)

Calculations

• Conversion from meters to millimeters. Example: 3.23 m = 3230 mm

Significant Figures

• Rules for determining the number of significant figures in a number.