1. Chemical Bonds
Study Guide Answers

2. 1. What is a polar molecule?
One that has a slightly positive end and a slightly negative end although the overall molecule is neutral

3. 2. All molecules are _________.
Neutral
Even a polar molecule like
water is still neutral overall,
even though it has regions
of charge

4. 3. Why do atoms combine to form a compound?
To become more stable

5. 4. What type of particle forms from covalent bonding?
Molecule

6. 5. What type of particle forms when an atom gains or loses electrons?
Ions

7. 6. How do the properties of a compound compare to the properties of the elements that make up the compound?
They are different

8. 7. When is an atom considered to be stable?
When its outer energy level is full (8 is considered full, even when the level can hold more)

9. 8. In a polar molecule, which atom would have a slightly negative charge?
The atom that attracts the electrons more

10. 9. What is a chemical formula?
Tells what elements a compound contains and the exact number of the atoms of each element in a unit of that compound

11. 10. What is a subscript?
It is a number written after a symbol that tells how many atoms of an element are in a unit of a compound

12. 11. What is a covalent bond?
Attraction that forms between atoms when they share electrons

13. 12. How many outer electrons make an atom stable?8*

14. 13. What is an ionic bond?
It is the force of attraction between the opposite charges of the ions in an ionic compound

15. 14. Why don’t the noble gases form compounds?
Because their outer energy level is filled with electrons

16. 15. What is a nonpolar molecule?
One in which electrons are shared equally in bonds

17. 16. What type of bond is formed in the figure below?
Ionic

18. 17. What type of bond is formed in the figure below?
Covalent

19. 18. Why is a molecule formed by 2 of the same atoms nonpolar?
Because each atom pulls the electrons by the same amount therefore the molecule doesn’t have a positive or negative end.

20. 19. A potassium atom has one electron in its outer energy level
19. A potassium atom has one electron in its outer energy level. A bromine atom has seven electrons in its outer energy level. Using a dot diagram of the two atoms, show how the potassium atom and the bromine atom form an ionic bond and then explain.
Potassium gives one electron to bromine. Bromine accepts one electron from potassium. Potassium forms a positive charge and bromine forms a negative charge.

21. 20.A Carbon atom has 4 valence electrons and Chlorine has 7 valence electrons. The molecule contains one atom of Carbon and 4 atoms of Chlorine. Draw the molecule. Show shared electrons using a line.  

22. 21. Explain why water is a polar molecule.
Oxygen has a stronger attraction to the shared pair of electrons than hydrogen does, leading to unequal
sharing of those electrons,
which causes regions of
slight negative (oxygen) and
slight positive (hydrogen)
charge on the molecule.

23. 22. Explain why diatomic nitrogen is a nonpolar molecule.
Two of the same atoms will have equal attraction for shared pairs of electrons.

24. The properties of a compound differ from the properties of the elements making up the compound.
True

25. Because a water molecule has a slight positive charge at one end and a slight negative charge at the other end, it is a nonpolar molecule.  
False- this is the cause of polarity

26. Molecules are neutral.
True

27. Atoms combine when the compound is less stable than the separate atoms.
False- Atoms combine to achieve stability

28. Particles formed from the covalent bonding of atoms are called ions.
False- covalent bonds produce molecules

29. When atoms gain or lose electrons, the charged particles that result are called molecules.
False- gaining and losing electrons is part of ionic bonding which produces ionic compounds

30. An atom is chemically unstable when its outer energy level contains all the electrons it can hold.
False- stability is achieved when valence shells are filled

31. The chlorine atoms in hydrogen chloride have a stronger attraction for the electrons than the hydrogen atoms do. The hydrogen chloride molecule is therefore a nonpolar covalent molecule.
False- this is polar because of unequal sharing

32. Elements chemically bond to become stable.
True-this is the point of this entire chapter

33. In a chemical formula, a subscript tells how many atoms of an element are in a unit of a compound.
True

34. Because each noble gas has an outer energy level that is completely filled with electrons, these elements form chemical bonds easily.
False- these elements are already stable so they do not bond

35. A covalent bond is the force of attraction between the opposite charges of the ions in an ionic compound.
False- this is an ionic bond if opposite charge holds the compound together

36. An element that loses electrons when bonding with other atoms develops a negative charge.
False- the loss of electrons which are negative leads to excess positive charge

37. A chemical formula tells what elements make up a compound and the ratios of the atoms of those elements.  
True

38. A bond that forms between atoms when they share electrons is an ionic bond.
False- sharing electrons is covalent bonding

39. The force of attraction between the opposite charges of the ions in a compound is a covalent bond.
False- this is ionic bonding

40. Molecules that do not have oppositely charged ends are nonpolar molecules.
True

41. A chemical bond is formed when atoms gain, lose, or share electrons.
True

42. A subscript indicates the charge on an ion.
False- superscripts represent charge on an atom

43. The word transfer summarizes covalent bonding, while sharing describes ionic bonding.
False- covalent bonding involves sharing and ionic involves transferring

44. Ionic compounds are charged, but made of neutral particles.
False- the compound is neutral but made of charged particles

45. Ionic compounds are made up of a metal and a nonmetal.
True

46. Two shared pairs of electrons represent a triple bond.
False- two shared pairs is a double bond

47. NaBr

48. O2

49. NH3

50. Al2S3

51. MgI2

52. H20

53. CBr4

54. AlCl3