Chemistry: Atomic Structure and Chemical Bonds

Atomic Structure and Properties

• Atoms are composed of protons, neutrons, and electrons
• Atomic mass is the mass of an atom
• Atomic number is the number of protons in an atom
• Electron cloud surrounds the nucleus, electrons occupy energy levels
• Valence electrons are electrons in the outermost energy level
• Periodic table organizes elements based on properties
• Ions are atoms with a net positive or negative charge due to gaining or losing electrons
• Isotopes are atoms of the same element with different numbers of neutrons
• Radioactive isotopes emit radiation

Chemical Bonds and Compounds

• Atoms bond to form molecules or compounds
• Ionic bonds involve the transfer of electrons
• Covalent bonds involve the sharing of electrons
• Nonpolar covalent bonds share electrons equally
• Polar covalent bonds share electrons unequally
• Hydrogen bonds are weak attractions between molecules
• Organic compounds contain carbon, inorganic compounds do not

Water

• Water is a polar molecule with hydrogen bonds
• Properties of water include cohesion, surface tension, adhesion, high specific heat, and high heat of vaporization
• Water is a universal solvent
• Water is essential for biological systems
• Solutions are mixtures with a solvent and a solute
• Electrolytes dissociate in water to form ions
• Hydrophobic molecules do not dissolve in water
• Hydrophilic molecules dissolve in water
• Amphipathic molecules have both hydrophobic and hydrophilic parts

Biomolecules

• Biomolecules are molecules essential for life
• Types of biomolecules include carbohydrates, lipids, proteins, and nucleic acids
• Monomers are the building blocks, polymers are formed by linking monomers
• Dehydration synthesis forms polymers, hydrolysis breaks them down
• Proteins have primary, secondary, tertiary, and quaternary structures.