Chemistry 3A Name:
Chapter 4
Problem Set IV
Spring ‘09
Instructor: B. Williams
This is not a graded assignment. Do not turn in.
1) Use a periodic table to complete the list of elements, symbols, group numbers, and atomic number.
ElementName / ChemicalSymbol / Group
Number / Atomic number
Boron
/ B / IIIA / 5Lithium / Li / IA / 3
Magnesium / Mg / IIA / 12
Sulfur / S / VIA / 16
Chlorine
/ Cl / VIIA / 17Carbon
/ C / IVA / 6Chromium
/ Cr / VIB / 24Strontium
/ Sr / IIA / 38Silver
/ Ag / IB / 47Bromine
/ Br / VIIA / 35Barium
/ Ba / IIA / 56Tin
/ Sn / IVA / 50Selenium
/ Se / VIA / 34Gold
/ Au / IB / 79Zinc
/ Zn / IIB / 30Beryllium
/ Be / IIA / 4Argon
/ Ar / VIIIA / 18Phosphorous
/ P / VA / 15Aluminum
/ Al / IIIA / 13Calcium
/ Ca / IIA / 20Titanium
/ Ti / IVB / 22Bismuth
/ Bi / VA / 83Krypton
/ Kr / VIIIA / 362) Complete the following table for each neutral atom.
ElementName / Nuclear
Symbol / Atomic
No. / Mass
No. / Number of
Protons / Number of Neutrons / Number of Electrons
Nickel
/ / 28 / 58 / 28 / 30 / 28Calcium / / 20 / 40 / 20 / 20 / 20
Chlorine / / 17 / 35 / 17 / 18 / 17
Barium / / 56 / 137 / 56 / 81 / 56
3) Two isotopes of copper are naturally occurring: at 69.15% (62.930 amu) and at 30.85% (64.928 amu). Calculate the atomic mass of copper.
4) Write the symbol and the name for each X and the number of protons and neutrons.
ElementName / Chemical Symbol / Number of
Protons / Number of Neutrons
/ Neon / Ne / 10 / 10
/ Magnesium / Mg / 12 / 12
/ Silicon / Si / 14 / 14
/ Neon / Ne / 10 / 11
/ Phosphorous / P / 15 / 16
5) Write the electron arrangement for each of the following atoms. Indicate how many electrons are in the outer energy level of each atom.
a) sulfur 2e-, 8e-, 6e- 6e-
b) oxygen 2e-, 6e- 6e-
c) argon 2e-, 8e-, 8e- 8e-
d) an atom with Z = 17 2e-, 8e-, 7e- 7e-
6) State the number of electrons in the outermost energy level (valence electrons), the group number for each element, and the electron-dot symbol for the given elements:
Element Valence Electrons Group number Dot symbol
a) carbon 4 IVA
b) aluminum 3 IIIA
c) silicon 4 IVA
d) potassium 1 IA
e) fluorine 7 VIIA
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