Chemistry Atomic Structure and Bonding

Chemistry

Atomic Structure

• Atom: smallest unit of matter, consisting of protons, neutrons, and electrons
• Protons: positively charged, found in nucleus, determine atomic number
• Neutrons: no charge, found in nucleus, determine atomic mass
• Electrons: negatively charged, found in electron cloud, participate in chemical reactions

Chemical Bonding

• Types of bonds:
  • Ionic bonds: transfer of electrons between atoms
  • Covalent bonds: sharing of electrons between atoms
  • Hydrogen bonds: weak attraction between atoms
• Bonding theories:
  • Valence Shell Electron Pair Repulsion (VSEPR) theory: predicts molecular shape
  • Molecular Orbital (MO) theory: describes molecular bonding and antibonding

Chemical Reactions

• Types of reactions:
  • Synthesis: combination of reactants to form a product
  • Decomposition: breakdown of a reactant into products
  • Single displacement: one element replaces another in a compound
  • Combustion: reaction involving oxygen and heat
• Reaction rates:
  • Factors affecting reaction rates: concentration, temperature, catalysts, surface area
  • Rate equations: describe the rate of a reaction

Physics

Mechanics

• Kinematics: study of motion without considering forces
  • Describing motion: position, velocity, acceleration, displacement
  • Types of motion: linear, circular, rotational
• Dynamics: study of motion with forces
  • Newton's laws:
    • First law: inertia, objects at rest or in motion remain so unless acted upon by a force
    • Second law: force and acceleration, F = ma
    • Third law: action and reaction, every action has an equal and opposite reaction

Energy and Work

• Types of energy:
  • Kinetic energy: energy of motion
  • Potential energy: energy of position or state
  • Thermal energy: energy of heat
  • Electromagnetic energy: energy of light and radiation
• Work: transfer of energy from one object to another
  • Work-energy theorem: work done on an object is equal to the change in its kinetic energy

Thermodynamics

• Laws of thermodynamics:
  • Zeroth law: temperature, if two systems are in thermal equilibrium with a third system, they are also in thermal equilibrium with each other
  • First law: energy conservation, energy cannot be created or destroyed, only converted
  • Second law: entropy, total entropy of a closed system always increases over time
  • Third law: absolute zero, it is impossible to reach absolute zero by any finite number of processes

Atomic Structure

• Atom: the smallest unit of matter, composed of protons, neutrons, and electrons
• Protons: positively charged, found in the nucleus, determine the atomic number of an element
• Neutrons: have no charge, found in the nucleus, contribute to the atomic mass of an element
• Electrons: negatively charged, found in the electron cloud, participate in chemical reactions and bond formation

Chemical Bonding

• Ionic bonds: form through the transfer of electrons between atoms, resulting in ions with opposite charges
• Covalent bonds: form through the sharing of electrons between atoms, resulting in a molecule
• Hydrogen bonds: weak attractions between atoms, important in molecular structure and function
• Valence Shell Electron Pair Repulsion (VSEPR) theory: predicts molecular shape based on electron pair arrangement
• Molecular Orbital (MO) theory: describes molecular bonding and antibonding, including sigma and pi bonds

Chemical Reactions

• Synthesis reactions: combine reactants to form a new product
• Decomposition reactions: break down a reactant into multiple products
• Single displacement reactions: one element replaces another in a compound
• Combustion reactions: involve oxygen and heat, resulting in a chemical change
• Reaction rates: influenced by factors such as concentration, temperature, catalysts, and surface area
• Rate equations: mathematical expressions describing the rate of a reaction

Physics

Mechanics

• Kinematics: describes motion without considering forces, including position, velocity, acceleration, and displacement
• Dynamics: studies motion considering forces, including Newton's laws of motion
• Newton's first law: an object at rest or in motion remains so unless acted upon by an external force
• Newton's second law: force is proportional to acceleration, F = ma
• Newton's third law: every action has an equal and opposite reaction

Energy and Work

• Kinetic energy: energy of motion, dependent on an object's velocity
• Potential energy: energy of position or state, dependent on an object's position or configuration
• Thermal energy: energy of heat, transferred between systems
• Electromagnetic energy: energy of light and radiation, including visible and non-visible forms
• Work: transfer of energy from one object to another, quantified by the work-energy theorem

Thermodynamics

• Laws of thermodynamics:
  • Zeroth law: thermal equilibrium, allowing temperature measurement
  • First law: energy conservation, energy cannot be created or destroyed, only converted
  • Second law: entropy, total entropy of a closed system always increases over time
  • Third law: absolute zero, impossible to reach by any finite number of processes