Atomic Structure and Chemical Bonding

Atomic Structure

• Atoms are the fundamental building blocks of matter.
• Atoms are composed of a nucleus containing protons and neutrons, with electrons orbiting the nucleus.
• Protons are positively charged, electrons are negatively charged, and neutrons are neutral.
• The number of protons in an atom determines its atomic number and element.
• Isotopes of an element have the same number of protons but different numbers of neutrons.
• Atomic mass is the average mass of all isotopes of an element, considering their relative abundance.
• Electron configurations describe the arrangement of electrons in orbitals around the nucleus, based on energy levels and sublevels.

Bonding

• Chemical bonds form when atoms interact to achieve a more stable electron configuration.
• Ionic bonds form when one atom gives up one or more electrons to another atom, forming ions with opposite charges that attract.
• Covalent bonds form when atoms share one or more pairs of electrons.
• Metallic bonds form when valence electrons are shared among a lattice of metal ions.
• Properties of substances are often related to the types of bonds present.

Periodic Table

• The periodic table organizes elements based on their atomic number and properties.
• Elements in a vertical column (group) have similar chemical properties.
• Elements in a horizontal row (period) show trends in atomic radius, ionization energy, and electronegativity.
• Elements are classified as metals, nonmetals, and metalloids based on their properties.
• Metals generally conduct electricity and heat, are malleable and ductile, and have a shiny luster.
• Nonmetals generally do not conduct electricity or heat, are brittle, and exist as gases, liquids, or solids.
• Metalloids have properties intermediate between metals and nonmetals.

Chemical Reactions

• Chemical reactions involve the breaking and forming of chemical bonds.
• Reactants are the substances that undergo a chemical change, and products are the substances formed from the reaction.
• Chemical equations represent chemical reactions using chemical formulas and coefficients to show the relative amounts of reactants and products.
• Balancing chemical equations ensures that the number of atoms of each element is the same on both sides of the equation.
• Reaction rates are influenced by factors such as reactant concentration, temperature, and catalysts.
• Types of reactions include synthesis, decomposition, single replacement, double replacement, and combustion.

Stoichiometry

• Stoichiometry is the quantitative relationship between reactants and products in a chemical reaction.
• Mole is the unit used to measure the amount of a substance containing Avogadro's number of particles.
• Molar mass is the mass of one mole of a substance.
• Stoichiometric calculations involve using balanced chemical equations to determine the amounts of reactants and products involved in a reaction.
• Calculations include mass-mass, mass-mole, mole-mole, and volume-mole relationships.

Solutions

• A solution is a homogeneous mixture of two or more substances.
• The solute is the substance being dissolved, and the solvent is the substance doing the dissolving.
• Concentration of a solution expresses the amount of solute present in a given amount of solution or solvent.
• Various methods exist for expressing concentration, including molarity, molality, and percent by mass.
• Properties of solutions, such as boiling point elevation and freezing point depression, differ from those of the pure solvent.

Acids and Bases

• Acids and bases are chemical compounds that have distinct properties.
• Acids generally taste sour, react with metals, and turn blue litmus paper red.
• Bases generally taste bitter, feel slippery, and turn red litmus paper blue.
• The pH scale is used to measure the acidity or basicity of a solution.
• A neutral solution has a pH of 7.
• Strong acids and bases completely dissociate in water, while weak acids and bases only partially dissociate.
• Neutralization reactions occur when an acid and a base react to form a salt and water.

Thermodynamics

• Thermodynamics deals with the relationship between heat, work, and energy in chemical systems.
• The first law of thermodynamics states that energy cannot be created or destroyed, only transformed.
• The second law of thermodynamics states that the entropy of the universe always increases in spontaneous processes.
• Enthalpy (H) is a measure of the heat content of a system.
• Changes in enthalpy (ΔH) describe the heat absorbed or released during a reaction.
• Entropy (S) is a measure of the disorder or randomness in a system.
• Gibbs free energy (G) combines enthalpy and entropy to predict the spontaneity of a reaction.

Organic Chemistry

• Organic chemistry is the study of carbon-containing compounds.
• Carbon's ability to form four covalent bonds allows for a vast array of structures.
• Hydrocarbons are organic compounds composed only of carbon and hydrogen.
• Functional groups are specific groups of atoms within organic molecules that determine their chemical reactivity.
• Isomers are molecules with the same molecular formula but different structures.
• Common functional groups include alcohols, aldehydes, ketones, carboxylic acids, and amines.

Explore atomic structure, including protons, neutrons, and electrons. Learn about isotopes, atomic mass, and electron configurations. Understand chemical bonds, including ionic and covalent bonds, and how atoms interact to achieve stable electron configurations.