ATOMS & COMPOUNDS

• Atomic theory of matter


  Everything around us is made up of tiny particles called atoms
• Atomic theory of matter


  All matter is made up of tiny particles called atoms, which are indivisible and retain their unique properties
• Elements are composed of identical atoms, while compounds are formed by the combination of atoms from different elements in specific ratios
• Atoms are conserved in chemical reactions, merely rearranging to form new compounds
• Atomic models


  Scientific representations of the structure of an atom
• Atomic models


  • Thomson's Plum Pudding Model
  • Rutherford's Nuclear Model
  • Bohr's Model
  • Quantum Mechanical Model
• Thomson's Plum Pudding Model


  • Atom likened to a positively charged "pudding" with negatively charged electrons embedded throughout, like "plums"
• Rutherford's Nuclear Model


  • Atoms have a small, dense, positively charged nucleus at the center, with electrons orbiting around it like planets around the sun
• Bohr's Model


  • Electrons orbiting the nucleus in specific energy levels or shells, similar to planets in fixed orbits around the sun
• Quantum Mechanical Model


  • Electrons described as waves of probability within specific regions around the nucleus called orbitals
• Main components of an atom

  • Protons
  • Neutrons
  • Electrons
• Protons


  Positively charged particles found in the nucleus of an atom, determining the element's identity
• Neutrons


  Neutral particles located in the nucleus alongside protons, helping to stabilize the nucleus and contribute to the atom's mass
• Electrons


  Negatively charged particles that orbit the nucleus in specific energy levels or shells, involved in chemical bonding and determining the atom's reactivity
• Key properties of atoms

  • Atomic Number
  • Mass Number
  • Isotopes
  • Electron Configuration
  • Valence Electrons
  • Atomic Mass
• Atomic Number


  The number of protons in the nucleus of an atom, determining the element's identity
• Mass Number


  The total number of protons and neutrons in the nucleus of an atom, helping to determine the atom's mass
• Isotopes


  Atoms of the same element with different numbers of neutrons, having the same atomic number but different mass numbers
• Electron Configuration


  Describes how electrons are arranged in energy levels or shells around the nucleus, influencing an atom's chemical properties and reactivity
• Valence Electrons


  The electrons in the outermost energy level of an atom, involved in bonding with other atoms to form molecules and compounds
• Atomic Mass


  The average mass of an atom, taking into account the mass and abundance of its isotopes
• Principles governing electron configuration

  • Pauli Exclusion Principle
  • Aufbau Principle
  • Hund's Rule
• Pauli Exclusion Principle


  No two electrons in an atom can have the same set of four quantum numbers
• Aufbau Principle


  Electrons occupy the lowest energy levels first before moving to higher energy levels
• Hund's Rule


  Electrons will fill orbitals of equal energy singly before pairing up, maximizing the total spin of the atom
• Quantum mechanics


  A branch of physics that deals with the behavior of particles at a very small scale, such as atoms and subatomic particles
• Key concepts in quantum mechanics

  • Wave-Particle Duality
  • Quantization of Energy
  • Uncertainty Principle
  • Quantum Superposition
  • Quantum Entanglement
• Quantum mechanics plays a crucial role in understanding the behavior of matter and energy at the atomic and subatomic levels, leading to advancements in various fields such as electronics, computing, and telecommunications
• Compounds


  Formed when atoms of different elements chemically combine with each other
• Types of chemical bonds that hold atoms together in compounds

  • Ionic Bonds
  • Covalent Bonds
  • Metallic Bonds
  • Hydrogen Bonds
• Ionic Bonds


  Formed when one atom transfers electrons to another atom, resulting in the formation of positively charged ions (cations) and negatively charged ions (anions) that are attracted to each other due to their opposite charges
• Covalent Bonds


  Atoms share electrons to achieve a full outer electron shell, creating a strong bond between the atoms. Can be polar (unequal sharing of electrons) or nonpolar (equal sharing of electrons)
• Metallic Bonds


  Metal atoms share their electrons freely among a sea of electrons, allowing metals to conduct electricity and heat effectively
• Hydrogen Bonds


  Weak bonds that form between a hydrogen atom covalently bonded to a highly electronegative atom (such as oxygen or nitrogen) and another electronegative atom in a different molecule
• Ideal gas law


  A fundamental principle in chemistry and physics that describes the behavior of an ideal gas under various conditions
• Fundamental gas laws


  • Boyle's Law
  • Charles's Law
  • Avogadro's Law
• Boyle's Law


  At constant temperature, the pressure of a gas is inversely proportional to its volume
• Charles's Law


  At constant pressure, the volume of a gas is directly proportional to its temperature in kelvin
• Avogadro's Law


  Equal volumes of gases at the same temperature and pressure contain an equal number of molecules