Key-Honors Bonding Review 4/5/11
1. Be able to determine bond type, and draw the proper dot diagram.
2. For the following, determine bond type and draw the correct diagram:
A. BaO
b. PCl
c. SiCl
d. SrN
ionic
covalent
covalent ionic
e. PbCl
ionic
f. AlI
covalent
g. TeBr
covalent
Drawings will be done in class.
Also, add h. PbF and i. CaI
3. Define
ionic bond-transfer of electrons with attraction of opposite charges; usually between
metal and nonmetal.
covalent bond-bonding by sharing of electrons; usually between nonmetals.
cation-positive ion- formed by loss of electrons.
anion-negative ion- formed by gain of electrons.
molecule-neutral particle formed by a covalent bond.
diatomic molecule-two atoms of the same element covalently bonded.
octet rule-states that atoms bond to get a full outer shell; to obtain a noble gas electron
configuration which is an octet.
oxidation number, valence, charge-tells the combining ability of an atom; shows the
number of electrons lost, gained or shared in a chemical bond.
electron dot diagram(notation)-shows the symbol of an element surrounded by dots in a
specific pattern to show the valance electrons.
formula unit-the smallest complete unit of an ionic compound.
electronegativity-how strongly an atom attracts electrons.
polyatomic ion-a group of atoms covalently bonded that behaves as one ion.
VSEPR model-valence shell electron pair repulsion-states that molecules adjust their
shape so that valence electrons are as far apart as possible.
polar molecule- occurs when bonding electrons are shared unequally between atoms,
giving a molecule slightly opposite-charged poles.
Van Der Waal’s Forces:
dipoleforces- attractive forces between the oppositely charged ends of polar molecules,
corresponding to higher melting and boiling points.
dispersion forces-weaker temporary attractive forces caused by the moving electrons
within atoms that form the molecules.
hydrogen bonds-always involve hydrogen, and occur when hydrogen bonds covalently to
another more highly electronegative element; the strongest intermolecular forces; a type
of strong dipole force. Hydrogen bonding corresponds to higher boiling point. metallic
bond-are modeled as a “sea” of electrons shared among metal atoms. The valence
electrons are free to move around.
hydrate-a salt that is bonded to a specific number of water molecules.
Law of Definite composition-states that a specific compound must always contain the
same elements in the same ratio.
4. How many electrons do we assume a metal atom will lose? the number in its outer
shell: 1, 2, or 3.(4 for Sn and Pb)
5. Why do atoms form bonds? to complete the outer shell.
6. How many electrons do we expect a nonmetal to gain? enough to fill the outer shell: 1,
2, or 3.
7. Which type of bond forms no charges? covalent
8. Which type of bond forms molecules? covalent
9. Looking at your periodic table, list the diatomic molecules. H, N, O, F, Cl, Br, I How
are they bonded? covalent
10. Describe/recognize a triple bond. When atoms share 3 pair of electrons.
11. Describe/recognize a double bond. When atoms share 2 pair of electrons.
12. 38 protons with 36 electrons gives what charge? +2
13. 33 Protons with 36 electrons gives what charge? -3
14. What metallic properties are caused by metallic bonding? conductivity, malleability,
ductility, and shiny luster of metals.
15. Why will the HF molecule be highly polar? Fluorine has a very high
electronegativity, while hydrogen is very low. Which VSEPR shapes will be polar and
which ones will not? Bent and trigonal pyramidal are polar; linear, trigonal planar, and
tetrahedryl are nonpolar.
16. What is a polyatomic ion? a group of atoms bonded together covalently, which
behave as one ion. losing or gaining electrons. How is a polyatomic ion bonded
together within itself? covalent
17. Explain how the crisscross method works for writing ionic formulas. If charges do not
cancel, drop signs and criss-cross to obtain proper subscripts. What should be the sum of
ionic charges in a compound? 0
18. What is the charge for nonmetals in Family IVA? -4 VA? -3 VIA? -2 VIIA? -1
19. What is the charge for metals in family IA? +1 IIA? +2 IIIA? +3 IVA? +4
20. Regarding the criss-cross method, what is the formula ratio when oxidation numbers
cancel as in +2-2 or +3-3? 1:1, such as BaO.
21. What does it mean for an element to obtain a Noble Gas electron configuration during
bonding? they obtain an octet to become stable. Metals lose down to the previous noble
gas. Nonmetals gain up to the next noble gas.
22. Why do smaller differences in electronegativity result in covalent bonds, while larger
differences result in ionic bonds? When the difference in electronegativity is smaller,
electrons will be shared instead of transferred.
23. How is AlPO4 made of both ionic and covalent bonds? PO4-3 is a polyatomic ion,
held together by a covalent bond. In AlPO4 Al is held to PO4 by an ionic bond. Al loses 3
electrons and phosphate gains 3 electrons.
24. Be able to match a formula to the correct molecular shape, number of bonding pairs,
and number of nonbonding pairs for linear, trigonal planar, tetrahedral, trigonal
pyramidal, and bent shapes found on your VSEPR chart(1st 5).
25. Tell the shape for each of the following molecules: a. a halogen bonds to a family 15
element-trigonal pyramidal b. 4 atoms bond to carbon or silicon-tetrahedryl c. 2
halogen atoms bond to a VIA element having 2 unshared pair of electrons-bent
d. 2 halogen atoms bond to beryllium or magnesium with no lone pair of electrons-linear
e. 3 halogen atoms bond to boron or aluminum with no nonbonding pairs of electronstrigonal planar.
26. What happens to radius when an atom loses electrons? radius decreases What
happens when an atom gains electrons? it increases
27. Compare and contrast the properties of ionic and covalent compounds.
Ionic
Covalent
Conduct electricity.
Nonconductors
Crystalline solids.
Solid, liquid, or gas
High melting point.
High solubility in water.
Low melting point
Low.
Formula unit.
Molecule.
Electron transfer.
Sharing.
28. Which type of bond or attraction is the strongest? network solid
29. Which intermolecular attraction is strongest? hydrogen bond
Weakest? dispersion forces
30. Was the hydrate lab, when water was taken from copper sulfate pentahydrate,
endothermic or exothermic? endothermic Why was it important to let the dish cool? So
that convection would not allow the dish to rise and seem lighter.Why should you not
allow the dish to cool for too long? The anhydrous copper sulfate will begin to rehydrate
and take on more mass.