Chemical Bonding and Nomenclature Quiz

Study Notes

Chemical Bonding and Nomenclature

Ionic Compounds:
- Formed by the electrostatic attraction between oppositely charged ions.
- Example: ClO3- (heteronuclear polyatomic)
Molecular Formulas:
- Represent the actual number of atoms of each element in a molecule.
- Example: Butane (C4H10)
Lattice Energy:
- The energy required to separate one mole of an ionic compound into its gaseous ions.
- Higher lattice energy indicates stronger ionic bonding.
- Example: MgF2 has the highest lattice energy.
Electronegativity:
- The ability of an atom to attract electrons towards itself in a covalent bond.
- Higher electronegativity indicates a stronger attraction for electrons.
- Example: Silicon (Si) has the highest electronegativity among the choices.
Percent Composition:
- The percentage by mass of each element in a compound.
- Formula: (mass of element / molar mass of compound) * 100%
- Example: KNO3 has 38.67% potassium (K) by mass.
Naming Compounds:
- Ionic Compounds: Metal cation name + nonmetal anion name with suffix -ide.
  - Example: Chromium (IV) chloride (CrCl4)
- Covalent Compounds: Prefix indicating the number of atoms + nonmetal name + suffix -ide.
  - Example: Carbon tetrachloride (CCl4)
Acids:
- Binary acids: Hydro + nonmetal name + ic acid.
  - Example: Hydrochloric acid (HCl)
- Ternary acids: Nonmetal name + ic acid.
  - Example: Hypobromous acid (HBrO)
Empirical Formula:
- The simplest whole-number ratio of atoms of each element in a compound.
- Example: A compound containing 40.0% C and 6.71% H has an empirical formula of CH2O.

Molecular Structure and Bonding

Valence Electrons: Electrons in the outermost shell of an atom, which participate in chemical bonding.
- Example: PO43- has 32 valence electrons.
Electron Domains: Regions of electron density around a central atom, including bonding pairs and lone pairs.
- Example: SO42- has 4 electron domains around the sulfur atom.
Bond Length: The distance between the nuclei of two bonded atoms.
- Longer bond lengths typically indicate weaker bonds.
Bond Order: The number of chemical bonds between two atoms.
- Example: P2 has a triple bond (bond order = 3).
Molecular Geometry: The three-dimensional arrangement of atoms in a molecule.
- Determined by minimizing electron-electron repulsion.
- Example: SO42- has a tetrahedral molecular geometry.
Electron Domain Geometry (EDG): The arrangement of electron domains around a central atom.
- Example: SO42- has a tetrahedral electron domain geometry.
Formal Charge: The hypothetical charge on an atom in a molecule if electrons were shared equally between atoms.
- Calculated using the formula: Formal charge = valence electrons - lone pair electrons - ½(bonding electrons)
- Example: The formal charge of sulfur in SCN- is 0.
VSEPR Classification: A system for predicting molecular geometry based on the number of electron domains around a central atom.
- Example: NH3 is classified as AB3U1.

Resonance Structures

Resonance Structures: Two or more Lewis structures that can represent the same molecule or ion.
- They differ in the placement of electrons but have the same relative positions of atoms.
- The actual structure is a hybrid of all resonance structures.
- Example: The molecule with the Lewis structure shown in the text has a valid resonance structure that shifts the double bond to a different position.