Structure of Matter

Structure of Matter

Matter

• Matter is the substance that comprises everything in the universe.
• It is defined as anything that possesses mass and occupies space.
• Examples of matter include gold, orange juice, and helium.
• Sound and space are not considered matter.

Composition of Matter

• Atoms constitute the fundamental units of matter.
• Elements are substances that cannot be broken down into simpler forms.
• Approximately 100 elements combine to form all matter in the universe.
• Examples of elements include oxygen, hydrogen, carbon, silver, and potassium.

Periodic Table of Elements

• The periodic table organizes elements based on their properties.
• Elements are arranged in groups (columns) and periods (rows).
• Key elements mentioned include hydrogen (H), carbon (C), oxygen (O), potassium (K), and silver (Ag).

Properties of Matter

• Matter possesses two primary types of properties: physical and chemical.
• Physical properties: Characteristics observable without altering the substance's atomic/molecular structure.
  • Examples: color, odor, density, melting point, and boiling point.
• Chemical properties: Describe how matter can transform into other substances.
  • Examples: burning, reacting with acid, and undergoing chemical reactions.

Chemical vs. Physical Changes

• Physical Change: Mixing sugar and water
• Chemical Change: Your body using sugar to keep you alive or Car door rusting over time.
• Physical Change: Rain puddles evaporating.

Atomic Structure

• Nucleus: The central core of an atom, containing:
  • Protons: Positively charged particles.
  • Neutrons: Electrically neutral particles.
• Electrons: Negatively charged particles that surround the nucleus.

Rutherford's Experiment

• Rutherford conducted an experiment where positively charged particles were directed at a thin gold foil.
• Most particles passed through undeflected, but some were deflected.
• Conclusions:
  • Atoms are primarily empty space.
  • The nucleus is a dense, positively charged mass.

Atomic Composition

• Each element is characterized by a unique number of protons.
• Examples:
  • Hydrogen (H) has 1 proton.
  • Carbon (C) has 6 protons.
  • Oxygen (O) has 8 protons.
• The periodic table lists elements with their symbols, atomic numbers, and atomic masses.
  • Hydrogen: Symbol H, Atomic Number 1, Atomic Mass 1.00794
  • Carbon: Symbol C, Atomic Number 6, Atomic Mass 12.011
  • Oxygen: Symbol O, Atomic Number 8, Atomic Mass 15.9994

Periodic Table Practice

• Atomic Number: Represents the number of protons in the nucleus, equivalent to the number of electrons in a neutral atom.
• Symbol: A one- or two-letter abbreviation representing the element, often derived from its common or Latin name.
• Name: The common name of the element.
• Atomic Mass: The mass of an atom of the element.
• Elements are arranged in the periodic table in ascending order of their atomic number.

Atomic Mass Explained

• For smaller atoms, the atomic mass is approximately double the number of protons.

Isotope Symbols

• Isotope symbols represent specific atoms, like cobalt-59.
• Mass Number: The sum of protons and neutrons in the nucleus.

Determining Atomic Composition

• Using the mass number and atomic number, we can determine the number of protons, neutrons, and electrons in an atom.
• Example: For an atom with a mass number of 59 and 27 protons:
  • Number of electrons = 27 (since the atom is neutral)
  • Number of neutrons = 59 - 27 = 32

Practice Problems

• Example: 92 protons, 146 neutrons.

Ions

• Ions are atoms with an electrical charge (positive or negative) due to an imbalance between protons and electrons.
• Cations: Possess more protons than electrons, resulting in a positive charge.
• Anions: Possess more electrons than protons, resulting in a negative charge.

Isotopes

• Isotopes are atoms of the same element with varying numbers of neutrons.
• Example: Isotopes of carbon:
  • Carbon-14: 6 protons, 8 neutrons.
  • Carbon-12: 6 protons, 6 neutrons.
• The number following the element name (e.g.,