Chemistry Atomic Structure and Bonding

Atomic Structure

• Atoms are the fundamental building blocks of matter.
• Atoms consist of a nucleus containing protons and neutrons, surrounded by orbiting electrons.
• Protons have a positive charge, electrons have a negative charge, and neutrons have no charge.
• The number of protons in an atom's nucleus defines its atomic number and dictates the element.
• The atomic mass is the sum of protons and neutrons.
• Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
• Electron shells or orbitals dictate the energy level of the electron.

Chemical Bonding

• Chemical bonds form when atoms interact to achieve a more stable electron configuration.
• Ionic bonds form when one atom transfers an electron to another, creating ions with opposite charges that attract.
• Covalent bonds form when atoms share electrons.
• Metallic bonds form when valence electrons are shared among a lattice of metal atoms.
• Bond strength influences the properties of the resulting compound (e.g., melting point, boiling point).
• Polar covalent bonds occur when electrons are shared unequally, creating a partial positive and partial negative charge.
• Nonpolar covalent bonds occur when electrons are shared equally.

Periodic Table

• Elements are arranged in a periodic table based on their atomic number and recurring properties.
• Elements in the same column (group) have similar chemical properties.
• Elements in the same row (period) exhibit trends in properties, like increasing ionization energy and atomic size.
• Metals tend to be good conductors of heat and electricity, while nonmetals generally are poor conductors.

Chemical Reactions

• Chemical reactions involve the rearrangement of atoms to form new substances.
• Reactants are the starting substances.
• Products are the substances formed after the reaction.
• A balanced chemical equation shows the same number of atoms of each element on both sides of the equation.
• Reactions can be exothermic (releasing heat) or endothermic (absorbing heat).
• Chemical reactions are driven by changes in energy and can involve various factors like temperature, concentration of reactants, and presence of a catalyst.

Stoichiometry

• Stoichiometry is the calculation of the quantities of reactants and products in a chemical reaction.
• Mole is the standard unit for measuring amounts of substances.
• Mole ratios from balanced equations allow for calculations of the amounts of reactants and products.

Acids and Bases

• Acids are substances that release hydrogen ions (H+) in water.
• Bases are substances that release hydroxide ions (OH-) in water.
• The pH scale measures the acidity or basicity of a solution.
• Strong acids and bases completely dissociate in water.
• Weak acids and bases only partially dissociate.
• Neutralization reactions occur when acids and bases react to form water and a salt.

Solutions

• Solutions are homogeneous mixtures of two or more substances.
• Solvents are the substances that dissolve other substances.
• Solutes are the substances that are dissolved.
• Concentration expresses the amount of solute in a given amount of solvent or solution.
• Different methods are used to measure concentrations of solutions (e.g., molarity, molality).

Organic Chemistry

• Organic chemistry focuses on the study of carbon-containing compounds.
• Many organic molecules have diverse structures due to carbon's ability to form four bonds.
• Functional groups are specific groups of atoms within organic molecules that determine chemical properties.
• Classes of organic compounds are characterized by their functional groups.