School Science Lessons
Table 2. Table of the elements
2019-06-02
Please send comments to: J.Elfick@uq.edu.au

Terms applied to the Table of the elements
Actinides, actinoids: 2.1.0
Atomic mass units, amu: 2.4.0
Atomic number and mass number: 2.2.0
Atomic weight: 2.3.0
Awt
Elements: 2.5.0
Free element metals: 2.6.0
Heavy metals: 2.7.0
Lanthanides: 2.11.0
Metalloids: 2.8.0
Radiation, ionizing radiation, Geiger counter: 2.9.0
Radioactive carbon dating: 2.10.1
Radioactive elements: 2.10.0
Rare earth elements, lanthanides: 2.11.0
Symbol of an element: 2.12.0
Table 1. Periodic Table

Table of the elements
Symbol Atomic number
Atomic weight
Group
Name
Ac
89
Awt
03
Actinium
Al
13
26.98
13
Aluminium
Am 95 Awt
09
Americium
Sb 51 121.8
15
Antimony
Ar 18 39.95
18
Argon
As 33 74.92
15
Arsenic
At 85 Awt
17
Astatine
Ba 56 137.3
02
Barium
Bk 97 Awt
11
Berkelium
Be 04 9.012
02
Beryllium
Bi 83 209.0
15
Bismuth
Bh
107
Awt
07
Bohrium
B 05 10.81
13
Boron
Br 35 79.90
17
Bromine
Cd 48 112.4
12
Cadmium
Cs 55 132.9 01
Caesium
Ca 20 40.08
02
Calcium
Cf 98 Awt
12
Californium
C 06 12.00
14
Carbon
Ce 58 140.1
04
Cerium
Cl 17 Awt
17
Chlorine
Cr 24 52.00
06
Chromium
Co
27
58.93
09
Cobalt
Cn
112
285
12
Copernicium
Cu 29 63.55
11
Copper
Cm 96 Awt
10
Curium
Ds
110
Awt
10
Darmstadtium
Db
105
Awt
05
Dubnium
Dy 66 162.5
12
Dysprosium
Es 99 Awt
13
Einsteinium
Er 68 167.3
14
Erbium
Eu 63 152.0
09
Europium
Fm 100 Awt
14
Fermium
F 09 19.00
17
Fluorine
Fr 87 Awt
01
Francium
Gd 64 157.3
10
Gadolinium
Ga 31 69.72
13
Gallium
Ge 32 72.63
14
Germanium
Au 79 197.0
11
Gold
Hf 72 178.5
04
Hafnium
Hs
108
Awt
08
Hassium
He 02 4.003
18
Helium
Ho 67 164.9
13
Holmium
H 01
1.008
01
Hydrogen
In 49 114.8
13
Indium
I
53 126.9
17
Iodine
Ir 77 192.2
09
Iridium
Fe 26 55.85
08
Iron
Kr 36 83.80
18
Krypton
La 57 138.9
03
Lanthanum
Lw 103 Awt
17
Lawrencium
Pb 82 207.2
14
Lead
Li 03 6.96
01
Lithium
Lu 71 175.0
17
Lutetium
Mg 12 24.31
02
Magnesium
Mn 25 54.94
07
Manganese
Mt 109
Awt
09
Meitnerium
Md 101 Awt
15
Mendelevium
Hg 80 200.6
12
Mercury
Mo 42 95.96
06
Molybdenum
Nd 60 144.2
06
Neodymium
Ne 10 20.18
18
Neon
Np 93 Awt
07
Neptunium
Ni 28 58.69
10
Nickel
Nb 41 92.91
05
Niobium
N 07 14.00
05
Nitrogen
No 102 Awt
16
Nobelium
Os 76 190.2
08
Osmium
O 08 16.00
16
Oxygen
Pd 46 106.4
10
Palladium
P 15 30.97
15
Phosphorus
Pt 78 195.1
10
Platinum
Pu 94 Awt
08
Plutonium
Po 84 Awt
16
Polonium
K 19 39.10
01
Potassium
Pr 59 140.9
05
Praseodymium
Pm 61 Awt
07
Promethium
Pa 91 231.9
05
Proactinium
Ra 88 Awt
02
Radium
Rn 86 Awt
18
Radon
Re 75 186.2
07
Rhenium
Rh 45 102.9
09
Rhodium
Rg
111
Awt
11
Roentgenium
Rb 37 85.47
01
Rubidium
Ru 44 101.1
08
Ruthenium
Rf
104
Awt
04
Rutherfordium
Sm 62 150.4
08
Samarium
Sc 21 44.96
03
Scandium
Sg
106
Awt
06
Seaborgium
Se 34 78.96
16
Selenium
Si 14 28.08
14
Silicon
Ag 47 107.9
11
Silver
Na 11 23.00
01
Sodium
Sr 38 87.62
02
Strontium
S 16 32.05
16
Sulfur
Ta 73 180.9
05
Tantalum
Tc 43 Awt
07
Technetium
Te 52 127.8
16
Tellurium
Tb 65 158.9
11
Terbium
Tl 81 204.3
13
Thallium
Th 90 232.0
04
Thorium
Tm 69 168.9
15
Thulium
Sn 50 118.7
14
Tin
Ti 22 47.87
04
Titanium
W
74
183.8
06
Tungsten
U 92 238.0
06
Uranium
V 23 50.94
05
Vanadium
Xe 54 131.3
18
Xenon
Yb 70 173.1
16
Ytterbium
Y 39 88.91
03
Yttrium
Zn 30 65.38
12
Zinc
Zr 40 91.22
04
Zirconium

2.1.0 Actinides, actinoids
Actinoids, rare earth elements, from 89 Ac, to 103 Lr inclusive, are metals shown separately below the main table, in period P7a.
Actinides can be represented by Ac. The valence of their cations varies. They are all radioactive. They form part of the group of
transition metals.
Actinium | Thorium | Protactinium | Uranium | Neptunium | Plutonium | Americium | Curium | Berkelium | Californium | Einsteinium |
a href="#FmS">Fermium | Mendelevium | Nobelium | Lawrencium
2.2.0 Atomic number and mass number
Atomic number, Z, is the number of protons in the nucleus of an atom of an element.
Mass number, A, atomic mass number, nucleon number, is the total number of protons and neutrons in the nucleus of an atom of an
element
Atomic number is shown in the left subscript position and mass number is shown in the left superscript position
See diagram 2.2.0: Carbon-12, Uranium-238, Oxygen-16
2.3.0 Atomic weight
Atomic weight, relative atomic mass (r.a.m.), of an element, is the ratio of the average atomic mass of an atom of an element,
including the common isotopes, to 1/12 the mass of an atom of carbon-12, the unified atomic mass unit.
Awt, Atomic weight - elements with no stable isotopes
Chlorine is 75% chlorine-35 and 25% chlorine-37, r.a.m. = 35.4527, so atomic weight is usually quoted as 35.5.
For atomic weight values listed for elements with no stable isotopes. See IUPAC Periodic Table of the Elements, 2011-01-21.
2.4.0 Atomic mass units, amu
Atomic mass units (u) are used to state the mass of an individual particle, e.g. 1 atom of oxygen has a mass of 16.00 u.
The atomic mass unit is 1/12 of the mass of 12C. Mass of 1 amu = 1.66 × 10−27 kg
2.5.0 Elements
Elements, chemical elements, are substances that cannot be separated into simpler substances.
All matter consists of single elements or combinations of elements.
The periodic table includes 92 naturally occurring elements and 8 or more radioactive elements synthesized by nuclear reactions.
2.6.0 Free element metals
Free element metals are found in free elemental form, e.g. Gold | Copper.
2.7.0 Heavy metals
3.10.0 Poisons and First Aid (Table)
Heavy metals, a metal of relatively high density, specific gravity > 5, metal of high relative atomic weight, especially if poisonous.
The term "heavy metals" has been used in legislation related to chemical hazards and the safe use of chemicals with the legal regulations
in specifying a list of heavy metals to which they apply.
Heavy metals defined as elements commonly used in industry and generically toxic to animals and to aerobic and anaerobic processes
may include As, Cd, Cr, Cu, Pb, Hg, Ni, Se, Zn.
So Copper | Lead | Mercury | Zinc, are called "heavy metals", if they cause pollution.
The term "heavy metal" is not exact.
For example, although Aluminium and Beryllium are toxic, they are not called heavy metals.
2.8.0 Metalloids
Metalloids have properties between metals and non-metals.
The metalloids are as follows:
| Boron | Silicon | Germanium | Arsenic | Antimony | Tellurium |
Also some chemists include | Polonium | and | Astatine. |

2.9.0 Radiation, ionizing radiation, Geiger counter
See: Geiger Counters (Commercial)
See diagram 2.9: Geiger counter
Alpha particles have two protons and two neutrons, Helium nucleus
Beta particles are electrons.
Gamma rays and X-rays are pure photons.
A Geiger counter is used to detect alpha particles, beta particles and gamma rays.
A radionuclide (radioisotope, isotope), emits radioactivity, gamma rays and may be used in nuclear medicine.
The five types of ionizing radiation
1. Alpha radiation, α radiation + alpha particle
Uranium -238 --> thorium-234
238U92 --> 234Th90 + 4He2 + energy
An alpha particle can be shown as 4He2 or 4α2.
uranium-238 --> thorium-234 + alpha particle + gamma rays (gamma photon)
Uranium, symbol U, atomic number 92, is in group 6, period P7a of the Periodic Table.
Alpha radiation travels a very short distance through air, cannot penetrate skin or clothing, but it can be harmful if alpha-emitting
materials inhaled, swallowed, or absorbed through open wounds.
Transuranic elements, have atomic number > 92

2. Beta radiation, β radiation
Carbon-14 --> nitrogen-14 + beta particle + antineutrino
14C6 --> 14N7 + 0β-1 + electron antineutrino ( ̅νe) + energy
Some useful Beta emitters:
phosphorous-32,
tritium (H-3),
carbon-14,
strontium-90, and
lead-210.
3. Gamma radiation, γ radiation
Iodine-131 --> xenon 131 + gamma ray + beta particle
131I53 --> 131Xe54 + 0β-1 + 0γ0
The three most useful gamma radionuclides are:
cobalt-60,
cesium-137,
and technetium-99m.
4. X-rays: 27.23
5. Ultraviolet rays, Ultraviolet radiation (UV): 27.24
Ionizing radiation only wavelengths < 200 nm (called Vacuum UV or VUV), occurs in the atmosphere
Absorbed dose of ionizing radiation = energy absorbed / mass of tissue = J / kg, Grays (Gy)
Dose equivalent = absorbed dose × quality factor, Sieverts (Sv).
Quality factor is the comparative ionizing effect of radiation
Quality factors:
Alpha particles 20,
Neutrons >10 k3V 10 (only from nuclear reactions or neutron bombs),
Beta particles 1, Gamma rays 1, X-rays 1.
Background radiation comes from space radiation,
e.g. cosmic rays at high altitude, terrestrial radiation,
e.g. rocks,
e.g. radon-220, ingested thorium, potassium-40, manufactured radiation, coal power stations, medical treatment,
e.g. X-rays.
2.10.0 Radioactive element, stable isotope, half life
Nuclear, Geiger Counter, (Commercial)
Half-life from change in number of radioactive atoms - Equipment for senior physics practicals
By Todd Helmenstine
Technetium Tc-91, 4.21 x 106 years
Promethium Pm-145, 17.4 years
Polonium Po-209, 102 years
Astatine At-210, 8.1 hours
Radon Rn-222, 3.82 days
Francium Fr-223, 22 minutes
Radium Ra-226, 1600 years
Actinium Ac-227, 21.77 years
Thorium Th-229, 7.54 x 104 years
Protactinium Pa-231, 3.28 x 104 years
Uranium U-236, 2.34 x 107 years
Neptunium Np-237, 2.14 x 106 years
Plutonium Pu-244, 8.00 x 107 years
Americium Am-243, 7370 years
Curium Cm-247, 1.56 x 107 years
Berkelium Bk-247, 1380 years
Californium Cf-251, 898 years
Einsteinium Es-252, 471.7 days
Fermium Fm-257, 100.5 days
Mendelevium Md-258, 51.5 days
Nobelium No-259, 58 minutes
Lawrencium Lr-262, 4 hours
Rutherfordium Rf-265, 13 hours
Dubnium Db-268, 32 hours
Seaborgium Sg-271, 2.4 minutes
Bohrium Bh-267, 17 seconds
Hassium Hs-269, 9.7 seconds
Meitnerium Mt-276, 0.72 seconds
Darmstadtium Ds-281, 11.1 seconds
Roentgenium Rg-281, 26 seconds
Copernicium Cn-285, 29 seconds
Ununtrium Uut-284, 0.48 seconds
Flerovium Fl-289, 2.65 seconds
Ununpentium Uup-289, 87 milliseconds
Livermorium Lv-293, 61 milliseconds
2.10.1 Radioactive carbon dating
The radioactive isotope of carbon 14C has half-life 5700 years.
The most abundant carbon isotope is 12C and ratio of 12C / 14C in the environment is constant enough in the environment and so in the
tissues of living organisms.
At the death of an organism the amount of 14C decays exponentially, so the age of a fossil organism can be estimated by comparing
its 12C / 14C ratio with the current value.
No carbon dating can be done for after 1950 because of contamination of the atmosphere by nuclear explosions.
2.11.0 Rare earth elements, lanthanides
Lanthanides rare earth elements (rare earth metals), atomic numbers 57 La * to 71 Lu, are 15 metals shown separately below in the
Periodic table, period P6a.
They are all named after where they were originally found in Sweden.
The "rare earths" are not "rare"!
If Lanthanides are represented by Ln, they all form trivalent cations Ln3+.
Lanthanum | Cerium | Praseodymium | Neodymium | Promethium | Samarium | Europium | Gadolinium | Terbium | Dysprosium |
| Holmium | Erbium | Thulium | Ytterbium | Lutetium
The IUPAC adds Scandium, Sc, and Yttrium, Y, to the list of rare earth elements because they have similar chemical properties and
are often found in the same ores as the lanthanides.
Scandium | Yttrium
2.12.0 Symbol of an element
Symbol of an element, e.g. H for Hydrogen.
Atomic symbols, chemical formula notation, e.g. Ac, were mainly invented by the Swedish chemist Jacob Berzelius (1779-1848).