Chemical Bonding and Nomenclature Quiz

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.