1. Ch-8 review

2. Which is a typical characteristic of an ionic compound?
Electron pairs are shared among atoms.
The ionic compound has a low solubility in water.
The ionic compound is described as a molecule.
The ionic compound has a high melting point.

3. What is shown by the structural formula of a molecule or polyatomic ion?
the arrangement of bonded atoms
the number of metallic bonds
the number of ionic bonds
the shapes of molecular orbitals

4. Which of these elements does not exist as a diatomic molecule?Ne H F I

5. How do atoms achieve noble-gas electron configurations in single covalent bonds?
One atom completely loses two electrons to the other atom in the bond.
Two atoms share two pairs of electrons.
Two atoms share two electrons.
Two atoms share one electron.

6. Why do atoms share electrons in covalent bonds?
to become ions and attract each other
to attain a noble-gas electron configuration
to become more polar
to increase their atomic numbers

7. Which of the following elements can form diatomic molecules held together by triple covalent bonds?
carbon
fluorine
oxygen
nitrogen

8. Which noble gas has the same electron configuration as the oxygen in a water molecule?
helium
argon
neon
xenon

9. Which elements can form diatomic molecules joined by a single covalent bond?
hydrogen only
halogens only
halogens and members of the oxygen group only
hydrogen and the halogens only

10. Which of the following is the name given to the pairs of valence electrons that do not participate in bonding in diatomic oxygen molecules?
unvalenced pair
inner pair
outer pair
unshared pair

11. A molecule with a single covalent bond is ____.
Cl 2
N 2

12. Once formed, how are coordinate covalent bonds different from other covalent bonds?
They are stronger.
They are weaker.
They are more ionic in character.
There is no difference.

13. both bonding electrons come from the oxygen atom
When H forms a bond with H2 O to form the hydronium ion H 3O +, this bond is called a coordinate covalent bond because ____.
both bonding electrons come from the oxygen atom
it forms an especially strong bond
the electrons are equally shared
the oxygen no longer has eight valence electrons

14. How many valid electron dot formulas—having the same number of electron pairs for a molecule or ion—can be written when a resonance structure occurs?
2 only
1 only
2 or more

15. How many electrons can occupy a single molecular orbital?2 1 4

16. According to VSEPR theory, molecules adjust their shapes to keep which of the following as far apart as possible?
pairs of valence electrons
mobile electrons
inner shell electrons
the electrons closest to the nuclei

17. What causes water molecules to have a bent shape, according to VSEPR theory?
repulsive forces between unshared pairs of electrons
interaction between the fixed orbitals of the unshared pairs of oxygen
ionic attraction and repulsion
the unusual location of the free electrons

18. What type of hybrid orbital exists in the methane molecule?sp
sp 3
sp 2
sp 3d 2

19. What is the shape of a molecule with a triple bond?
tetrahedral
bent
pyramidal
linear

20. What is thought to cause the dispersion forces?
attraction between ions
sharing of electron pairs
motion of electrons
differences in electronegativity

21. What are the weakest attractions between molecules?
ionic forces
covalent forces
Van der Waals forces
hydrogen forces

22. What causes hydrogen bonding?
attraction between ions
motion of electrons
sharing of electron pairs
bonding of a covalently bonded hydrogen atom with an unshared electron pair