atomic radius
- one-half of the distance from the center to center of two like atoms
Atomic
radius decreases as you go across a period from left to right.
Across the periodic table elements increase in the number of electrons
in their outer energy level and the number of protons in their nucleus.
The addition of positively charged protons and negatively charged electrons
leads to greater attraction and the outer energy level moves closer to
the nucleus.
Atomic radius increases as you go down a group or family. Each
row on the periodic table represents an energy level in an atom. As atoms
gain energy levels they are added the outter end. In addition, the inner
energy level electrons block the attraction between the positively charged
nucleus and the electrons in the outer energy level. This shielding effect
decreases the attraction between the nucleus and the outer energy level
electrons. This allows electrons to drift further away from the nucleus.
Highest
atomic radius:
cesium(55) : 265
pm
Lowest atomic radius:
helium(2) : 31
pm
Undefined:
(85)
(86)
(87)
(88)
(93)
(96)
(97)
(98)
(99)
(100)
(101)
(102)
(103)
(104)
(105)
(106)
(107)
(108)
(109)
(110)
(111)
(112)
(114)
|
|
|
atomic radius graph
X-
axis: atomic number Y-axis:
atomic radius (pm)
|
|
|
|
|
hydrogen |
1 |
37 |
helium |
2 |
31 |
lithium |
3 |
152 |
beryllium |
4 |
111 |
boron |
5 |
80 |
carbon |
6 |
77 |
nitrogen |
7 |
74 |
oxygen |
8 |
74 |
fluorine |
9 |
71 |
neon |
10 |
69 |
sodium |
11 |
186 |
magnesium |
12 |
160 |
aluminum |
13 |
143 |
silicon |
14 |
118 |
phosphorus |
15 |
110 |
sulfur |
16 |
103 |
chlorine |
17 |
99 |
argon |
18 |
97 |
potassium |
19 |
227 |
calcium |
20 |
197 |
scandium |
21 |
161 |
titanium |
22 |
145 |
vanadium |
23 |
131 |
chromium |
24 |
125 |
manganese |
25 |
137 |
iron |
26 |
124 |
cobalt |
27 |
125 |
nickel |
28 |
125 |
copper |
29 |
128 |
zinc |
30 |
133 |
gallium |
31 |
122 |
germanium |
32 |
123 |
arsenic |
33 |
125 |
selenium |
34 |
116 |
bromine |
35 |
114 |
krypton |
36 |
110 |
rubidium |
37 |
248 |
strontium |
38 |
215 |
yttrium |
39 |
178 |
zirconium |
40 |
159 |
niobium |
41 |
143 |
molybdenum |
42 |
136 |
technetium |
43 |
135 |
ruthenium |
44 |
133 |
rhodium |
45 |
135 |
palladium |
46 |
138 |
silver |
47 |
145 |
cadmium |
48 |
149 |
indium |
49 |
163 |
tin |
50 |
141 |
antimony |
51 |
145 |
tellurium |
52 |
143 |
iodine |
53 |
133 |
xenon |
54 |
130 |
|
 Click column
name to sort
See
other element trend graphs:
atomic
radius
boiling
point
electronegativity
ionization
energy
melting
point |
