NAME:_____________________________________________DATE:________________________PERIOD:____
WORKSHEET
“Atomic Structure and Mass Spectroscopy”
1.
Complete the following table:
Kind of Atom
Atomic
Number
chlorine
Mass
Number
Isotope
Number of
Protons
Number of
Electrons
Number of
Neutrons
35
28
58
40
18
selenium
2.
3.
40
What is the isotope symbol of the species composed of each of the following sets of subatomic
particles? (Watch for ions!)
a.
24 protons, 27 neutrons, 24 electrons
___________
b.
20 protons, 20 neutrons, 18 electrons
___________
c.
34 protons, 44 neutrons, 34 electrons
___________
d.
53 protons, 74 neutrons, 54 electrons
___________
Naturally occurring iron consists of four isotopes with the abundances indicated here. From the
masses and relative abundances of these isotopes, calculate the atomic weight of naturally occurring
iron.
Isotope
54
Fe
56
Fe
57
Fe
58
Fe
Isotopic Mass (amu)
53.9396
55.9349
56.9354
57.9333
% Natural Abundance
5.82
91.66
2.19
0.33
4.
Determine the atomic mass and the identity of the elements which have the following atomic spectra.
a.
b.
Atomic Mass = ___________ Identity of Element: _______________
Atomic Mass = ___________ Identity of Element: _______________
R1.
Equal volumes of equimolar solutions of ammonia and hydrochloric acid are combined. ____________
Indicate whether the resulting solution is acidic, basic, or neutral. Explain.
AP Free Response
In an experiment, a student is given 2.94 g of a mixture containing anhydrous MgCl 2 and KNO3. To determine
the percentage by mass of MgCl2 in the mixture, the student uses excess AgNO3(aq) to precipitate the chloride
as AgCl(s).
a.
Starting with the 2.94 g sample of the mixture dissolved in water, briefly describe the steps
necessary to quantitatively determine the mass of the AgCl precipitate.
b.
The student determine the mass of the AgCl precipitate to be 5.48 g. On the basis of this
information, calculate each of the following.
i.
The number of moles of MgCl2 in the original mixture.
ii.
The percent by mass of MgCl2 in the original mixture.