Assignment 05 ANSWERS
Lewis Diagrams of Selected Main Group Elements
(Items 1-25) For each element draw the Lewis structure of the element, write the total number of valence electrons the element has and
then write the noble gas electron configuration. Use examples to help you complete the table.
IA
IIA
IIIA
IVA
VA
VIA
VIIA
VIIIA
1
2
1s1
1s2
1
[He]2s2
:
Be
2
[He]2s2
[He]2s22p1
Mg:
[Ne]3s2p1
[Ne]3s2
[Ne]3s1
2
[Ar]4s
1
[Ar]4s2
4
3
[Ar]4s23d104p1
4
[Ar]4s23d104p2
6
5
[He]2s22p3
[He]2s22p4
5
[Ne]3s23p3
[Ne]3s2p2
Ca:
1
[He]2s22p2
3
2
1
4
3
6
7
[He]2s22p5
7
[Ne]3s23p5
Ne]3s23p4
5
6
[Ar]4s23d104p3
[Ar]4s23d104p4
7
[Ar]4s23d104p5
8
[He]2s22p6
8
[Ne]2s22p6
8
[Ar]4s23d104p6
Conclusion Questions:
1. How do the Lewis diagrams and electron configurations change as you move left to right through a period of the periodic chart?
First the s subshell is filled one box at a time until a maximum of two is reached (Groups IA and IIA). Then the d subshell is filled one
at a time (Periods 4 and 5; transition elements) or f and d subshells are filled (Periods 6 and 7; inner transition elements). Finally, the
p subshell is filled so that each orbital has one and then so that each orbital has two electrons.
2. What conclusions can you draw about the chemical properties of the elements in a particular period?
Because the outer electrons shells change configuration the chemical properties should change in a characteristic manner.
3. How do the Lewis diagrams and electron configurations change as you move top to bottom through a group in the periodic chart?
The Lewis diagrams change as the s and p configuration changes. The Lewis diagram is unaffected by the filling of the d and f subshells.
4. What conclusions can you draw about the chemical properties of the elements in a particular group?
They should be very similar because their valence electron configurations are identical.
5. What is the correlation of the number of valence electrons and the dots in the Lewis diagram?
They are the same.
6. What is the correlation of the number of dots in the Lewis diagram and the sum of the electrons in the s and p orbitals?
They are the same.
7. It is known that Li and F are very reactive – explosive if added to each other. Ne on the other hand does not chemically combine with anything.
Looking at the Lewis diagrams and electron configurations, propose a possible explanation for these observations.
Li only has to lose an electron to gain noble gas configuration while F needs to gain one electron to achieve the nearest noble gas
configuration. Thus, when added together a reaction should occur. Ne on the other hand already has a noble gas configuration and
therefore is happy with what it has.
Write the noble gas electron configuration and Lewis diagram for each atom or ion.
1. Neon
2. Manganese
3. Chloride ion (Cl-)
4. Calcium
[He]2s22p6
[Ar]4s23d5
[Ne]3s23p6
[Ar]
5. Phosphorus
6. Tin
7. Krypton
8. Phosphide ion (P-3)
[Ne]3s23p3
[Kr]5s24d105p2
[Ar]4s23d104p6
[Ne]3s23p6
9. Tin(II) ion
10. Zinc
11. Zirconium
12. Barium
[Kr]5s04d10
[Ar]4s23d10
[Kr] 5s24d2
[Xe]6s2