Matter, Trends, and Bonding Study Notes

• Study notes for Matter, Trends, and Bonding

Atomic Structure and the Periodic Table

• Atomic number identifies the number of protons in an atom's nucleus.
• Atomic mass is the total mass of protons and neutrons in an atom.
• The periodic table's layout organizes elements by atomic number and groups them with similar properties.

Ions and the Octet Rule

• Atoms gain or lose electrons to form ions, aiming to achieve a stable electron configuration like noble gases.
• The octet rule states that atoms tend to gain, lose, or share electrons to achieve a full outer electron shell of eight electrons.

Average Atomic Mass/Isotopic Abundance

• Average atomic mass is the weighted average of the masses of an element's isotopes.
• Isotopic abundance refers to the percentage of each isotope in a naturally occurring sample of an element.

The Periodic Table and Periodic Law

• Bohr-Rutherford diagrams show the arrangement of electrons in shells around the nucleus of an atom.
• Lewis structures use dots to represent valence electrons and show how atoms bond in molecules.

Periodic Trends in Atomic Properties

• Atomic radius generally increases down a group and decreases across a period.
• Ionic radius is the radius of an ion; cations are smaller and anions are larger than their parent atoms.
• Ionization energy is the energy required to remove an electron from an atom; it increases across a period and decreases down a group.
• Electron affinity is the energy change when an electron is added to an atom; it generally increases across a period.
• Electronegativity is the ability of an atom to attract electrons in a chemical bond; it increases across a period and decreases down a group.

Chemical Compounds and Bonding

• Ionic compounds are formed through the transfer of electrons between atoms, resulting in a lattice structure.
• Molecular elements consist of two or more atoms of the same element bonded together.
• Molecular compounds are formed through the sharing of electrons between atoms.

Chemical Bonding and Electronegativity (Intramolecular Forces)

• Ionic bonds are formed through electrostatic attraction between ions.
• Nonpolar covalent bonds involve equal sharing of electrons.
• Coordinate covalent bonds occur when one atom donates both electrons to the bond.
• Polar covalent bonds involve unequal sharing of electrons due to differences in electronegativity.

Chemical Formulas and Nomenclature (Naming Compounds)

• Naming binary ionic compounds involves writing the name of the metal followed by the nonmetal with an "-ide" ending.
• Polyatomic ions are groups of atoms with an overall charge.
• Hydrates are compounds that have water molecules incorporated into their crystal structure.
• Naming molecular compounds uses prefixes to indicate the number of atoms of each element.
• Acids are compounds that donate protons (H+) in water.
• Bases are compounds that accept protons in water.

Molecular Compounds and Intermolecular Forces

• Polar bonds occur when there is an unequal sharing of electrons between atoms in a molecule.
• Polar molecules have an uneven distribution of electron density, resulting in a dipole moment.

Intermolecular Forces

• Ion-dipole forces occur between an ion and a polar molecule.
• Dipole-dipole forces occur between polar molecules.
• London dispersion forces are weak, temporary forces that occur between all molecules.
• Hydrogen bonds are strong dipole-dipole forces between hydrogen and a highly electronegative atom (N, O, F).

Hydrogen Bonding and Water

• Hydrogen bonding plays a crucial role in the unique properties of water, such as its high boiling point and surface tension.