Science, Matter, Energy, & Systems

Science, Matter, Energy, & Systems

SCIENCE

  • Definition: A field of study focused on discovering how nature works and using that knowledge to describe what is likely to happen in nature.

MATTER

  • Definition: Anything that has mass and takes up space.
  • Physical states:
    • Solid
    • Liquid
    • Gas
  • Chemical forms:
    • Elements
    • Compounds

ELEMENTS AND COMPOUNDS

ELEMENT

  • Definition: A fundamental type of matter with a unique set of properties that cannot be broken down into simpler substances by chemical means.
  • Examples: Gold (Au), Mercury (Hg)

COMPOUNDS

  • Definition: Combinations of two or more different elements held together in fixed proportions.
  • Examples:
    • Water (H2O)
    • Sodium Chloride (NaCl)

STRUCTURE OF MATTER

ATOMS, MOLECULES, AND IONS

  • Atom: The smallest unit of matter.
  • Subatomic particles:
    1. Neutrons: With no electrical charge.
    2. Protons: Positively charged (+).
    3. Electrons: Negatively charged (−).
  • Nucleus: A dense region containing protons and neutrons at the center of an atom.
  • Example model: Simplified model of a carbon-12 atom.

ATOMIC NUMBER AND MASS NUMBER

  • Atomic number: Equal to the number of protons in the nucleus of an atom.
    • Example: Carbon (C), which has 6 protons, has an atomic number of 6.
  • Mass number: The total number of neutrons and protons in an atom’s nucleus.
    • Example: A carbon atom with 6 protons and 6 neutrons has a mass number of 12.

ISOTOPES

  • Definition: Forms of an element having the same atomic number but different mass numbers.
  • Isotopes of Carbon:
    • Carbon-12 (C-12): 6 protons