Download Chemical Bonds Study Guide Answer Key

Chemical Bonds Study Guide
Define the following:
1. Chemical formula - the way of expressing information about the proportions of atoms that
constitute a particular chemical compound, using element symbols and numbers.
2. Molecule- electrically neutral group of two or more atoms held together by chemical bonds
3. Valence electrons- electrons located in the outermost electron level of an atom
4. Octet rule- chemical rule of thumb that states that atoms want to have 8 valence electrons
5. ionic bonds- a type of chemical bond that involves a metal and a nonmetal; formed due to
the attraction of opposite charges on the cation and anion; formed when metals donate
electrons to nonmetals
6. ion- formed when an atom gains or loses an electron.
7. Cation- a positively charged ion formed when metals donate electrons
8. Anion- a negatively charged ion, formed when nonmetals accept electrons
9. oxidation number- the charge on an ion
10. metallic bonds- describes how metal atoms are held together in a solid
11. alloy- a combination of 2 or more elements, at least one is a metal
12. covalent bonds- bonds formed when nonmetals share electrons
13. polar bonds- covalent bonds that have a positive end and a negative end
14. dipoles- polar bonds
15. electronegativity- the ability of an atom to attract electrons
Use the following chemical formulas to determine the number of atoms/element.
1. H2O H: 2 O: 1
2. MgCl2 Mg: 1 Cl:2
3. C6H12O6 C:6 H:12 O: 6
4. Na2SO4 Na:2 S:1 O:4
Ionic Bonds
1. Ionic bonds form between metals and nonmetals
2. Metals typically donate electrons, while nonmetals accept electrons.
3. Name the following ionic bonds.
A. NaCl- sodium chloride
B. CaBr2- calcium bromide
C. BeO – beryllium oxide
D. Li2S- lithium sulfide
4. Complete the following table: Use Lewis structures for your illustrations. Be sure to diagram
movement of electrons. Include oxidation numbers.
Compounds
Symbols with
Oxidation Number
Formula
Na,Cl
Na+1
NaCl
K, S
K+1
S-2
K2S
Ca, F
Ca+2
F-1
CaF2
Mg, S
Mg+2
S-2
MgS
Al, O
Al+3
O-2
Al2O3
Cl-1
Illustration
Metallic Bonds
1. Metals are like cations floating in a sea of electrons, because the valence electrons of one atom
are shared with all surrounding atoms.
2. List and describe three properties of metals.
Shiny
Conduct electricity- electrons are free to move around
Ductile- can be drawn into thin wires
Malleable- can be hammered into shapes
3. Define and give 2 examples of metal alloys.
Alloys- combination of 2 or more elements, at least one is a metal
Examples- steel, sterling silver, 14K gold
Covalent Bonds
1. Covalent Bonds form between a nonmetal and a nonmetal
2. Covalent bonds form when 2 atoms share electrons.
3. Illustrate the following compounds using Lewis structures. Be sure to draw circles around
shared electrons.
A. CH4
D. CO2
B. CHCl3
D. N2
4. Complete the following table. Include + and - on polar bonds.
Bonded
Atoms
Bond Type
Li2S
Electronegat
ivity
Difference
1.5
NH3
0.9
Polar covalent
Ionic (metal and
nonmetal)
Which is
more
negative
S
N
Illustration
CS2
0
Nonpolar
covalent
Equal
H2
0
Nonpolar
covalent
equal
KBr
2.0
Ionic
Br
N2
0
Nonpolar
covalent
Equal
CCl4
0.5
Polar covalent
Cl
5. Name the following covalent bonds.
A. H2O- dihydrogen monoxide
B. NO2- nitrogen dioxide
C. CCl4- carbon tetrachloride
D. NH3- nitrogen trihydride
6. Complete the following table comparing ionic and covalent bonds.
Ionic Bonds
Metal and nonmetal
Donate and Accept Electrons
High melting and boiling points
Soluble in water (polar substances)
Conduct electricity when dissolved or
melted
Solid crystalline structure
Covalent Bonds
Nonmetal and nonmetal
Share electrons
Low melting and boiling points
Non-soluble in water (polar substances)
Does not conduct electricity
Solid, liquid, or gas