Covalent Compounds

Which statement is true about a molecule of H₂?

• a.) Each atom has an electron configuration like that of helium.

• b.) It is less stable then either of the hydrogen atoms by itself.

• c.) The electrons from both atoms travel within the molecular orbital.

• d.) Both (a) and (c).

A single covalent bond involves the sharing of

• only one electron.

• two electrons.

• three electrons.

• a variable number of electrons, which depends on the bonding atoms.

If two covalently bonded atoms move closer than a distance of the bond length, the potential bond energy of the atoms

• becomes negative.

• decreases.

• increases.

• remains constant.

The electrons involved in the formation of a covalent bond are

• transferred from one atom to another.

• valence electrons.

• found only in the s-orbitals.

• in filled orbitals.

Bond energy is the energy

• absorbed as a molecule forms.

• change as atoms become closer together.

• of two covalently bonded atoms.

• required to break one mole of similar bonds in a compound.

Bond length between two bonded atoms is

• the separation at which their potential energy is minimum.

• twice the diameter of the molecular orbital.

• the sum of the diameters of each of the two overlapping electron clouds.

• the separation at which the motion of each atom stops.

Which compound most likely has the greatest bond energy?

• Cl2; Cl - Cl bond length = 199 pm

• HCl; H -Cl bond length = 127 pm

• HF; H - Cl bond length 92 pm

• I2; I - I bond length = 266 pm

Nonpolar covalent bonds are not common because

• one atom usually attracts electrons more strongly.

• ions always form when atoms join.

• the electrons usually remain equally distant from both atoms.

• dipoles are rare in nature.

A covalent bond is formed when two atoms

• share an electron with each other.

• share one or more pairs of electrons with each other.

• gain electrons.

• gain and lose electrons.

The atom with the highest electronegativity among those listed below is likely to be

• H.

• Na.

• C.

• Cl.