Download worksheet 7b answers - Iowa State University

Leader: Sara
Course: Chem177
Instructor: Kingston
Supplemental Instruction
Date: Monday, November 3
Iowa State University
1) Effective Nuclear Charge: the net positive charge experienced by an electron in
a many-electron atom. What is the equation?
Zeff = Z – S
Z = atoms number (# of protons or electrons)
S = Shielding/Screening electrons
Same n: 0.35
n-1: 0.85
n-2,3+: 1
Worksheet 7B:
Periodic Table Trends
2) Write the electron configuration for the following, also include the calculated Zeff.
a. Bromine
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5
34-10-(18*.85)-(6*.35)=
b. Sulfur
1s2 2s2 2p6 3s2 3p4
16-2-(8*.85)-(5*.35)=
3) What atom has the LARGEST atomic radius?
Francium
4) What atom has the SMALLEST atomic radius?
Helium
5) Which of the following molecules would you expect to be Largest?
a. Br2
Cl2
Br2
b. NaCl
KCl
KBr
NaBr
KBr
6) If the charge of an atom changes, does the radius of the atom change?
Yes
Cations are smaller, anions are larger
7) Which is larger?
a. Mg or
Mg2+
b. I
or
Ic. Clor
Brd. For
Ne
3e. N
or
P38) Put the following in order of increasing radius:
BrSe2- Sr2+ Kr
Rb+
2+
+
Sr
Rb
Kr
Br
Se29) Which is higher: First, Second or third Ionization energy?
10) What element in the 3rd period will have the highest third ionization energy?/
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11) Show the Zeff trend on the periodic table:
Smaller Z eff
Larger Z eff
12) Show the atomic radius trend on the periodic table:
Smallest radius
Largest radius
13) Show the Ionization energy trend on the periodic table: (Energy it takes to
remove and electron)
Highest
Ionization energy
Lowest Ionization
energy
14) Show the Electron Affinity trend on the periodic table: (energy required to add an
electon to a gaseous atom/molecule) Exceptions 2nd column and Nitrogen column
Most Negative
Closest to 0
15) Show the Electronegativity trend on the periodic table: (ability of an atom in a
molecule or solid to attract electrons to itself numbers only make sence in comparison)
highest
lowest
Metal oxides are basic in nature
CaO(s) + H2O  Ca(OH)2
Non Metal Oxides are acidic
CO2 + H2O  H2CO3