Periodic Table of the Elements

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Solid
 
Liquid
 
Gas
1
H
1.0079
                
2
He
4.0026
3
Li
6.941
4
Be
9.01218
          
5
B
10.81
6
C
12
7
N
14.0067
8
O
15.99994
9
F
18.998403
10
Ne
20.179
11
Na
22.9898
12
Mg
24.305
          
13
Al
26.98154
14
Si
28.0855
15
P
30.97376
16
S
32.06
17
Cl
35.453
18
Ar
39.948
19
K
39.0983
20
Ca
40.08
21
Sc
44.9559
22
Ti
47.9
23
V
50.9415
24
Cr
51.996
25
Mn
54.938
26
Fe
55.847
27
Co
58.9332
28
Ni
58.71
29
Cu
63.546
30
Zn
65.38
31
Ga
69.737
32
Ge
72.59
33
As
74.9216
34
Se
78.96
35
Br
79.904
36
Kr
83.8
37
Rb
85.4678
38
Sr
87.62
39
Y
88.9059
40
Zr
91.22
41
Nb
92.9064
42
Mo
95.94
43
Tc
98.9062
44
Ru
101.07
45
Rh
102.9055
46
Pd
106.4
47
Ag
107.868
48
Cd
112.41
49
In
114.82
50
Sn
118.69
51
Sb
121.75
52
Te
127.6
53
I
126.9045
54
Xe
131.3
55
Cs
132.9045
56
Ba
137.33
57
La
138.9055
72
Hf
178.49
73
Ta
180.9479
74
W
183.85
75
Re
186.2
76
Os
190.2
77
Ir
192.22
78
Pt
195.09
79
Au
196.665
80
Hg
200.59
81
Tl
204.37
82
Pb
207.2
83
Bi
208.9808
84
Po
209
85
At
210
86
Rn
222
87
Fr
223
88
Ra
226.0254
89
Ac
227
104
Rf
261
105
Db
262
106
Sg
271
108
Hs
277
107
Bh
270
109
Mt
270
110
Ds
281
111
Uuu
272
112
Uub
277
113
Uut
284
114
Uuq
289
115
Uup
288
Lanthanide Series
58
Ce
140.12
59
Pr
140.9077
60
Nd
144.24
61
Pm
145
62
Sm
150.4
63
Eu
151.96
64
Gd
157.25
65
Tb
158.9254
66
Dy
162.5
67
Ho
164.9304
68
Er
167.26
69
Tm
168.9342
70
Yb
173.04
71
Lu
174.967
Actinide Series
90
Th
232.0381
91
Pa
231.0359
92
U
238.029
93
Np
237.0482
94
Pu
244
95
Am
243
96
Cm
247
97
Bk
247
98
Cf
251
99
Es
252
100
Fm
257
101
Md
258
102
No
259
103
Lr
262
Click on any of the squares above for more information on an element.

The following notes were taken by me while listening to Chem 1A Lectures 11 and 12 by Professor Heino Nitsche

Atomic Number and Mass:
  • Each element in the table has an assigned atomic number. Hydrogen (H) has atomic number 1, Helium (He) has atomic number 2, etc.
  • The atomic number indicates the number of protons in the nucleus. The total atomic weight of the element is equal to the sum of the weights of the nucleons (protons and neutrons) and electrons. An element is defined by the number of protons, but can have differing numbers of neutrons, resulting in different isotopes. For example, Carbon-12 has 6 protons and 6 neutrons, Carbon-13 has 6 protons and 7 neutrons, and Carbon-14 has 6 protons and 8 neutrons.
  • As the atomic number increases, the number of protons, neutrons, and electrons in each subsequent element increases, and thus the mass of the element also increases.
Groups:
  • The elements in a given group (column) of the periodic table have similar chemical properties because they have the same number of valence electrons.
  • In general, only the valence electrons take part in bonding with other atoms; thus, elements in a group have similar bonding behavior since they have the same number of valence electrons.
  • For example, in the first column (group) of the periodic table, the elements H, Li, and Na all have one valence electron in the s orbital, and thus only have one electron available for bonding with other atoms.
  • Similarly, in the last group (column) of the Periodic Table, all of the elements have their valence electron shells filled, so they are (for the most part) un-reactive with other elements; for this reason, we call this last group the "noble gases".
  • Elements within a group are called "homologues", because they exhibit similar chemical behavior.
Periods:
  • The elements in a given row (called a "period") all have the same quantum energy level (the "n" quantum number").
  • For example, all the elements in the first row have n=1, all the elements in the second period have n=2, etc. Each subsequent row (period) has a higher energy level for its ground state, since higher "n" quantum numbers indicate higher energy states.
  • As you traverse a period from left to right, the valence shells are filled, following the Aufbau principle
  • In the topmost period, the Hydrogen atom (H) has a single 1s electron, and Helium (He) has a filled valence shell with two electrons in the 1s shell.
  • In the second period, Li (Lithium) has one electron in the 2s shell, Be has two electrons in the 2s shell, B has three valence electrons (two 2s electrons, and one 2p electron).
  • Completing the 2nd period, Ne, a noble gas, has a completely filled valence electron shell with two 2s electrons and six 2p electrons.
  • In the 3rd period, you start with one electron in the 3s orbital (Na), and then add a second electron to the 3s orbital (Mg), and then fill the 3p orbital with six electrons as you progress from Al to Ar.
  • In the 4th period, there is an exception. After filling the 4s orbital with two electrons (Ca), you then fill the 3d orbitals with 10 electrons (Sc -> Zn).
  • Because the 3d orbitals are higher in energy than the 4s orbitals, but lower in energy than the 4p orbitals, we must first fill the 3d orbitals.
  • Similarly, for the 5th period, we fill the 4d orbitals after the 5s orbitals, but before filling the 5p orbitals.
  • In the sixth period, we first fill the 6s orbitals (Cs and Ba), and then add one electron to the 6p orbital (La). Before filling the rest of the 6p orbitals, we must first fill the 4f orbitals. These elements are shown in a separate row called the "Lathanide Series". One could argue that the Lanthanides, beginning with element number 58, should be listed in the sixth row following element number 57, La. After filling the 4f orbitals, we then continue in period 6 by filling the 5f orbitals. Finally, we finish filling the 6p orbitals, ending on Rn.
  • The seventh period is analogous to the sixth period. After filling the 7s orbital with two electrons (Ra), and adding a single 7p electron (Ac), we then need to fill the 5f orbitals as they are higher in energy than the 6p1 orbital, but lower in energy than the 6p2 (and 5d) orbitals. These elements are shown separately as the "Actinide series". Then, we fill the 5d orbitals, and finally the 6p orbitals.


Group Names:
  • The elements in the first group (column) of the Periodic Table are called Alkali Metals.
  • The elements in the second group (column) of the Periodic Table are called Alkaline Earth Metals.
  • Groups (columns) 3 through 12 are called "Transition Elements".
  • The elements in the second to last column (group) of the Periodic Table are called Halogens.
  • The elements in the last group (column) of the Periodic Table are called Noble Gases. With few exceptions, these elements are not very reactive, as their valence shells are completely filled.
Atomic Radius
  • Atomic radius decreases within a period, and increases within a group.
  • Within a period, as more protons are added, the protons bind more tightly to the electrons, reducing the radius.
  • Within a group, the effective charge of the protons is reduced by the shielding of the filled electron shells, and the outermost electrons are bound less tightly resulting in a larger atomic radius.
Ionization Energy:
  • The ionization energy is the amount of energy needed to extract a single electron from an atom, forming a positive ion (cation).
  • To remove an electron from an atom, one must add energy to that atom (endothermic).
  • Looking at a Group (column), one expects the ionization energy to decrease as one goes down the column. For example, Na (Sodium) has a higher ionization energy than Rb, because Rb has more filled electron shells shielding the protons, and thus has a lower effective positive charge with which it can bind the outermost electron.
  • By choosing the "Ionization Energy" radio button above, and then moving the scrollbar, you can see that the ionization energy decreases within a column (group).
  • Within a period, the ionization energy generally increases as the number of protons increases. There are some exceptions as the angular momentum quantum number changes (i.e. as we switch from s orbitals to p orbitals), and also as the first electron with anti-parallel spin is added while following Hund's Rule.
  • By choosing the "Ionization Energy" radio button above, and then moving the scrollbar, you can observe that the ionization energy increases within a row (period).
  • Note that the 1st ionization energy (energy required to remove the 1st electron) is less than the 2nd ionization energy (energy required to remove the second electron) because after removing the 1st electron, the remaining electrons are more tightly bound by the protons, causing the ionization energy to increase for each subsequent electron removal.
Electron Affinity:
  • The electron affinity indicates how likely an atom is to acquire another electron, forming a negative ion (anion).
  • When an atom acquires another electron, energy is released (exothermic).
  • Within a group, one expects the electron affinity to decrease as one goes down the column. For example, Cl has a higher electron affinity (is more likely to pull an electron from another atom) than Br, because Br has an additional filled electron shell shielding the protons, and thus has a lower effective positive charge with which to attract and bind to electrons.
  • By choosing the "Electron Affinity" radio button above, and then moving the scrollbar, you can observe how the electron affinity decreases within a column (group).
  • Similarly, you can observe how electron affinity increases within a period (row) as the number of protons increase.
Electronegativity
  • Electronegativity is the ability of an atom within a molecule to pull electrons away from a binding partner (another atom in the molecule).
  • Electronegativity increases within a Period as one travels from left to right in the Periodic Table.
  • Electronegativity decreases as one traverses a group (column) from top to bottom.
  • Francium (Fr) is the least electronegative element (we often say it is “electropositive”).
  • Flourine (F) is the most electronegative element; in a molecule, it will try to pull the binding electrons from other atoms in the molecule towards itself.
  • Looking at the difference between the electronegativity of two bonded atoms
    • If the difference is > 2.0, the bond is ionic. For example, NaCl is an ionic bond, as Sodium (Na) has “given” its electron to Chlorine (Cl).
    • If the difference is between .4 and 2.0, the bond is polarized covalent (partly ionic). For example, in HCl, the bond is covalent, but the shared electron spends most of its time closer to the Cl atom than the H atom, forming a dipole
    • If the difference is less than .4, the bond is covalent, and the electron is shared equally. For example, Cl-Cl is a perfectly covalent bond since both partners have the same electronegativity
  • If two atoms have a large difference in electronegativites, a large amount of energy will be released upon forming the bond. If two atoms have a small difference in electronegativities, the energy released on formation of the bond will be small.
Observations
  • Halides, having high ionization energies and high Electron Affinity, are more likely to acquire electrons from other atoms.
  • Metals, having low ionization energies, and low Electron Affinity, are more likely to give electrons to other atoms.
  • Non-metals often form anions (high electron affinity)
  • In general, elements on the right side of the periodic table are more likely to form anions (high electron affinity combined with high ionization energy), and elements on the left side of the period table are more likely to form cations (lower ionization energy and lower electron affinity).


Click on the column headings below to sort the elements in different ways.
 Atomic NumberSymbolNameAverage Atomic Weight (grams/mole)Oxidation StatesMelting Temperature (°C)Boiling Temperature (°C)Year DiscoveredDensity grams/cm3 (solid) or grams/liter (gas)Specific Heat Capacity J/(g K) (at 25° and 1 atm)Thermal Conductivity W/(cm K) (at 25° and 1atm, W = watt)First Ionic Potential (eV)Electron Affinity (eV)Electronegativity (eV)
More Info 1HHydrogen1.00791-259.14-252.8717660.089914.30.00181513.5980.752.2
More Info 2HeHelium4.0026 -272.2-268.9318680.17855.190.00151924.587  
More Info 3LiLithium6.9411180.54134218170.533.5820.8475.3920.620.98
More Info 4BeBeryllium9.0121821287247117981.851.82529.322 1.57
More Info 5BBoron10.8132076400018082.341.0260.278.30.282.04
More Info 6CCarbon124,235503825 2.260.7091.9611.261.262.55
More Info 7NNitrogen14.0067-3,3,5,4,2-209.86-195.817721.2511.0420.0002597914.534 3.04
More Info 8OOxygen15.99994-2-218.4-182.96 1.4290.920.00267413.6181.463.44
More Info 9FFlourine18.998403-1-220-188.1418861.6960.8240.00027917.4223.43.98
More Info 10NeNeon20.179 -248.67-246.0518980.91.030.00049321.564  
More Info 11NaSodium22.9898197.8882.918070.971.231.415.1390.550.93
More Info 12MgMagnesium24.3052650109017551.741.021.567.646 1.31
More Info 13AlAluminum26.981543660251918272.70.92.375.9860.441.61
More Info 14SiSilicon28.085541414326518242.330.711.498.1511.391.9
More Info 15PPhosphorous30.97376-3,3,5,444.228016691.820.7690.0023510.4860.752.19
More Info 16SSulfur32.06-2,2,4,6120444.67 2.070.710.0026910.362.082.58
More Info 17ClChlorine35.453-1,1,3,5,7-102-34.617743.2140.488.9E-0512.9673.163.16
More Info 18ArArgon39.948 -189.2-185.718941.7840.520.00017715.759  
More Info 19KPotassium39.0983163.775918070.890.7571.0254.3410.50.82
More Info 20CaCalcium40.082842148418081.550.6472.016.1130.041
More Info 21ScScandium44.955931541283618762.990.5680.1586.560.191.36
More Info 22TiTitanium47.941668328717914.540.5230.2196.830.081.54
More Info 23VVanadium50.94155,319103407180160.4890.3076.750.531.63
More Info 24CrChromium51.9966,3,21907467117977.150.4490.9376.7660.671.66
More Info 25MnManganese54.9387,6,4,2,31246206117747.30.480.07827.435 1.55
More Info 26FeIron55.8472,315382861 7.8740.4490.8027.870.1511.83
More Info 27CoCobalt58.93322,31495292717358.90.42117.880.661.88
More Info 28NiNickel58.712,31455391317518.90.4440.9077.6351.161.91
More Info 29CuCopper63.5462,110852562 8.960.3854.017.7261.241.9
More Info 30ZnZinc65.382420907 7.130.3881.169.394 1.65
More Info 31GaGallium69.737330220418755.910.3710.4065.10.31.81
More Info 32GeGermanium72.594939283318865.320.320.5997.8991.232.01
More Info 33AsArsenic74.9216-3,3,5817603 5.780.330.59.810.812.18
More Info 34SeSelenium78.962,-2,4,6221684.918174.790.320.02049.7522.022.55
More Info 35BrBromine79.904-1,1,5-7.258.7818263.120.2260.0012211.8143.362.96
More Info 36KrKrypton83.8 -156.6-152.318983.750.2489.49E-0513.999  
More Info 37RbRubidium85.4678138.8968818611.5320.3630.584.1770.490.82
More Info 38SrStrontium87.622777138218082.640.30.03535.6950.110.95
More Info 39YYttrium88.905931522334517944.470.30.1726.220.311.22
More Info 40ZrZirconium91.2241855440917896.510.2780.22696.630.431.33
More Info 41NbNiobium92.90645,32477474418018.570.2650.5376.760.91.6
More Info 42MoMolybdenum95.946,5,4,3,226234639177810.220.251.387.0990.752.16
More Info 43TcTechnetium98.90627215742651937110.240.5067.280.552.1
More Info 44RuRuthenium101.072,3,4,6,823344150184412.10.2381.177.361.052.2
More Info 45RhRhodium102.90552,3,419643695180312.410.2421.57.461.142.28
More Info 46PdPalladium106.42,4155529631803120.250.7188.340.562.2
More Info 47AgSilver107.86819622162 10.50.2354.297.5761.31.93
More Info 48CdCadmium112.41232176718178.690.2320.9688.993 1.69
More Info 49InIndium114.8231572072 7.310.2330.8165.7860.31.78
More Info 50SnTin118.694,22322702 7.260.2280.66597.3441.111.96
More Info 51SbAntimony121.75-3,3,56311587 6.680.2070.2438.6411.072.05
More Info 52TeTellurium127.6-2,2,4,6449.5989.817826.240.2020.02359.0091.972.1
More Info 53IIodine126.9045-1,1,5,7114184.3518114.920.1450.0044910.4513.062.66
More Info 54XeXenon131.3 -111.9-10818985.890.1585.69E-0512.13 2.6
More Info 55CsCesium132.904512867118601.930.240.3593.8940.470.79
More Info 56BaBarium137.332727189718083.620.2040.1845.2120.150.89
More Info 57LaLanthanum138.90553918346418396.150.190.1355.770.51.1
More Info 58CeCerium140.123,4798344318036.770.190.1145.54 1.12
More Info 59PrPraseodymium140.90773,4931352018856.770.1930.1255.46 1.13
More Info 60NdNeodumium144.2431021307419257.010.190.1655.53 1.14
More Info 61PmPromethium14531042300019147.26 0.155.554  
More Info 62SmSamarium150.43,21074179418797.520.1970.135.64 1.17
More Info 63EuEuropium151.963,2822152919015.240.1820.1395.67  
More Info 64GdGadolinium157.2531313327318807.90.2360.1066.15 1.2
More Info 65TbTerbium158.92543,41356323018438.230.180.1115.86  
More Info 66DyDysprosium162.531412256718868.550.1730.1075.94 1.22
More Info 67HoHolmium164.930431474270018788.80.1650.1626.018 1.23
More Info 68ErErbium167.2631529286819059.070.1680.156.11 1.24
More Info 69TmThulium168.93423,21545195018799.330.160.1686.184 1.25
More Info 70YbYtterbium173.043,2819119619076.90.1550.396.254  
More Info 71LuLutetium174.96731663340219079.840.150.16395.43 1
More Info 72HfHafnium178.49422334603192313.310.140.236.8301.3
More Info 73TaTantalum180.9479530175458180216.40.140.5757.890.321.5
More Info 74WTungsten183.856,5,4,3,234225555178319.30.131.747.980.861.7
More Info 75ReRhenium186.27,6,4,2,-131865596192520.80.1370.4797.880.151.9
More Info 76OsOsmium190.22,3,4,6,830335012180322.60.130.8768.71.12.2
More Info 77IrIridium192.222,3,4,624464428180322.50.131.479.11.572.2
More Info 78PtPlatinum195.092,417683825173521.450.130.71692.132.2
More Info 79AuGold196.6653,110642856 19.30.1283.179.2252.312.4
More Info 80HgMercury200.592,1-38.84356.58 13.530.140.083410.437 1.9
More Info 81TlThallium204.373,13041473186111.80.1290.4616.1080.21.8
More Info 82PbLead207.24,23281749 11.30.1290.3537.4160.361.8
More Info 83BiBismuth208.98083,5271156417539.790.1220.07877.2890.951.9
More Info 84PoPolonium2094,225496218989.2 0.28.421.92
More Info 85AtAstatine210-1,1,3,5,73023371940  0.017 2.82.2
More Info 86RnRadon222 -71-61.819009.730.0943.64E-0510.748  
More Info 87FrFrancium2231276771939  0.15 0.460.7
More Info 88RaRadium226.02542700173718985 0.1865.279 0.9
More Info 89AcActinium227310513198189910.070.120.125.17 1.1
More Info 90ThThorium232.0381417504788182811.720.1130.546.08 1.3
More Info 91PaProtactinium231.03595,415684027191315.4 0.475.89 1.5
More Info 92UUranium238.0296,5,4,311354131184119.10.120.2766.19 1.7
More Info 93NpNeptunium237.04826,5,4,36444000194020.2 0.0636.27 1.3
More Info 94PuPlutonium2446,5,4,36403228194019.7 0.06746.06 1.3
More Info 95AmAmericium2436,5,4,311762011194413.6  5.993  
More Info 96CmCurium247313453100194413.5  6.02  
More Info 97BkBerkelium2474,31050 194914  6.23  
More Info 98CfCalifornium2513900 1950   6.3  
More Info 99EsEinsteinium2523860 1952   6.42  
More Info 100FmFermium25731527 1952   6.5  
More Info 101MdMendelevium2583,2827 1955   6.58  
More Info 102NoNobelium2593,2827 1958   6.65  
More Info 103LrLawrencium26231627 1961      
More Info 104Rfrutherfordium261   1964      
More Info 105DbDubnium262   1967      
More Info 106Sgseaborgium271   1974      
More Info 107Bhbohrium270   1981      
More Info 108Hshassium277   1984      
More Info 109Mtmeitnerium270   1982      
More Info 110DsDarmstadtium281   1994      
More Info 111UuuUnununium272   1994      
More Info 112UubUnunbium277   1996      
More Info 113UutUnuntrium284   2004      
More Info 114UuqUnunquadium289   1999      
More Info 115UupUnunpentium288   2004      
 
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