Matter and Energy Quiz

Matter and Energy

• Matter: Anything that occupies space and has weight.
• Energy: A force that causes change or movement; does not have weight or occupy space.

Types of Energy

• Potential Energy: Stored energy, e.g., a lifted ball has potential energy due to its height.
• Kinetic Energy: Energy of motion, e.g., a falling ball exhibits kinetic energy.

Chemical Elements

• Definition: Basic substances that cannot be chemically broken down; composed of one type of atom.
• Four elements forming 96% of the human body:
  • Oxygen (O): Vital for respiration and cellular functions.
  • Carbon (C): Fundamental building block of organic molecules.
  • Hydrogen (H): Essential for water and organic compounds.
  • Nitrogen (N): Key component of proteins and nucleic acids.

Atoms

• Definition: Basic unit of matter, consisting of a nucleus surrounded by electrons; retains chemical properties of the element.

Subatomic Particles

• Protons:
  • Charge: Positive (+1)
  • Mass: Approximately 1 atomic mass unit
  • Location: Nucleus of the atom
• Neutrons:
  • Charge: Neutral (no charge)
  • Mass: Approximately 1 atomic mass unit
  • Location: Nucleus of the atom
• Electrons:
  • Charge: Negative
  • Mass: Much smaller than protons and neutrons
  • Location: Orbiting the nucleus in energy levels or electronic shells

Atomic Number and Mass

• Atomic Number: Number of protons in the nucleus; determines elemental identity (e.g., atomic number of carbon is 6).
• Atomic Mass: Weighted average mass of an element's isotopes; accounts for protons, neutrons, and electrons.

Isotopes and Radioisotopes

• Isotopes: Variants of elements with the same number of protons but different numbers of neutrons, leading to varying atomic masses (e.g., carbon-12 vs. carbon-14).
• Radioisotopes: Unstable isotopes that decay over time, releasing radiation and transforming into different substances (e.g., uranium-238 decaying into lead-206).

Molecules and Compounds

• Molecule: A group of two or more bonded atoms.
• Compound: A substance formed by chemically bonding two or more different elements in a fixed ratio (e.g., water (H2O) is a compound of hydrogen and oxygen in a 2:1 ratio).

Mixtures

• Mixture: A combination of two or more substances that are not chemically bonded; properties of individual substances remain intact (e.g., a mixture of sand and salt can be physically separated).