chemistry

• What is a covalent bond?

  A covalent bond is a bond formed when two atoms share electrons.
• Many elements found in nature exist as molecules
• What is a molecule?

  A molecule is a neutral group of atoms joined together by covalent bonds.
• Compounds that are formed when two or more atoms combine to form molecules are called molecular compound
• the substances that do NOT exist as molecules in nature.

  helium and neon
• List two general properties of molecular compounds

  low melting and boiling points and they exist as gases or liquids at room temperature
• What is a molecular formula?

  A molecular formula shows how many atoms of each element a molecule contains
• ethanol

  C2H6O
• ammonia

  NH3
• true or false? A molecular formula shows the arrangement of the atoms in a molecule. false
• What term describes the arrangement of atoms within a molecule?

  molecular structure
• Is the following sentence true or false? In a structural formula a shared pair of electrons is represented by two dashes. false
• .Structural formulas show the arrangement of atoms in molecules.
• A chemical bond formed when atoms share two pairs of electrons is called a(n).

  double covalent bond
• How many covalent bonds are in a nitrogen molecule?

  three
• Is the following sentence true or false? All diatomic molecules contain double bonds.

  false
• What is a coordinate covalent bond?

  It is a covalent bond in which one atom contributes both bonding electrons.
• What is bond dissociation energy?

  it is the energy required to break a covalently bonded atoms
• Is the following sentence true or false? Molecules with high bond dissociation energies are relatively unreactive. true
• What is the bond dissociation energy for a typical C — C covalent bond?

  347kj/mole
• The actual bonding in ozone is a hybrid of the extremes represented by its resonance forms.
• When can resonance structures be written for a molecule?

  when it is possible to write two or more valid electron dot structures for the molecule that have the same number of electron pairs
• What is a molecular orbital?

  When two atoms combine, their atomic orbitals overlap to produce orbitals that apply to the entire molecule.
• Is the following sentence true or false? Electrons first fill the antibonding molecular orbital to produce a stable covalent bond. false
• When two s atomic orbitals combine and form a molecular orbital, the bond that forms is called a(n) sigma bond.
• When the central atom of a molecule has unshared electrons, the bond angles will be smaller than when all the central atom’s electrons are shared.
• s the following sentence true or false? Orbital hybridization theory can describe both the shape and bonding of molecules. true
• What causes dispersion forces?

  Dispersion forces are caused by the motion of electrons.
• Is the following sentence true or false? Dispersion forces generally increase in strength as the number of electrons in a molecule increases. true
• The strongest of the intermolecular forces are

  hydrogen bonds
• What determines the physical properties of a compound?

  The physical properties depend on the type of bonding in the compound and intermolecular attractions
• 3. In covalent bonds, electrons are shared in such a way that the configuration is the same as a noble gas
• A single atom provides the shared electron pair in a coordinate covalent bond.
• A strong covalent bond has a large bond dissociation energy.
• The resonance forms of ozone show the extremes that make up the hybrid bonding of oxygen atoms
• .The VESPER theory is used by scientists to explain the three-dimensional shape of molecules.
• mensional shape of molecules. 9. Information about both molecular bonding and molecular shape is provided by orbital hybridization
• A slightly negative charge is found on the more electronegative atom when two atoms bond
• 1. Ionic and covalent bonds are both stronger than intermolecular attractions.
• The variance in intermolecular attractions explains the diversity of physical properties among covalent compounds.