9.1 Mass as a Fundamental Dimension
As we discussed in Chapter 6, from their day-to-day observations humans noticed that some
things were heavier than others and thus recognized the need for a physical quantity to describe
that observation. Early humans did not fully understand the concept of gravity; consequently,
the correct distinction between mass and weight was made later. Let us now look more care-
fully at mass as a physical variable. Consider the following. When you look around at your sur-
roundings, you will find that matter exists in various forms and shapes. You will also notice
that matter can change shape when its condition or its surroundings are changed. All objects
and living things are made of matter, and matter itself is made of atoms, or chemical elements.
There are 106 known chemical elements to date. Atoms of similar characteristics are grouped
together in a table, which is called theperiodic table of chemical elements. An example of the
chemical periodic table is shown in Figure 9.1.
Atoms are made up of even smaller particles we callelectrons,protons, andneutrons. In your first
chemistry class you will study these ideas in more detail, if you have not yet done so. Some of you
may decide to study chemical engineering, in which case you will spend much more time study-
ing chemistry. But for now, remember that atoms are the basic building blocks of all matter.9.1 Mass as a Fundamental Dimension 231
Actinide
seriesH
Li Be
Na Mg
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn
He
BCNOFNe
Al Si P S Cl Ar
Ga Ge As Se Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Db Sg Bh Hs Mt
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
Br
1
3 4
11 12
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
2
5 6 7 8 9 10
13 14 15 16 17 18
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
87 88 89 104 105 106 107 108 109 110 111 112
58 59 60 61 62 63 64 65 66 67 68 69 70 71
90 91 92 93 94 95 96 97 98 99 100 101 102 103
IA
IIA
IIIB IVB VB VIB VIIB
VIIIB
IB IIBIIIA IVA VA VIA VIIA
VIIIA
Uun Uuu Uub
114 116 118
1.0079 4.003
6.941 9.012
22.990 24.305
10.811 12.011
26.982 28.086
14.007 15.999
30.974 32.066
18.998 20.180
35.453 39.948
39.098 40.078
85.468 87.62
132.905 137.327
223 226.025
44.956 47.88
88.906 91.224
138.906 178.49
227.028 261
50.942 51.996
92.906 95.94
180.948 183.84
262 263
54.938 55.845
98 101.07
186.207 190.23
262 265
58.933
102.906
192.22
266
58.69 63.546
106.42 107.868
195.08 196.967
269 272
65.39 69.723
112.411 114.82
200.59 204.383
72.61
118.71
207.2
74.922
121.76
208.980
78.96
127.60
209
79.904
126.905
210
83.8
131.29
222
140.115 140.908
232.038 231.036
144.24 145
238.029 237.048
150.36
244
151.964 157.25
243 247
158.925 162.5
247 251
164.93
252
167.26
257
168.934
258
173.04
259
174.967
262
277
Lanthanide
series1 2 3 4 5 6 7
■Figure 9.1 The chemical elements to date (2010).
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