Periodic Table of Elements

Properties & Characteristics of Elements Unless otherwise noted, standard temperature (0°C) and pressure (1000 millibars) are assumed.
At.#	Sym.	Name	At.Wt.	Iso- topes	Val.	Melt (°C)	Boil (°C)	Sp.Gr.	Remarks
1	H	hydrogen	1.008	1, 2, 3	1	-259	-253	0.08987 ×10^-3	Lightest and most abundant element in the universe, present on earth combined with numerous other elements to form water, ammonia, carbohydrates, hydrocarbons, acids, bases, and many other substances. Chemically similar to alkali metals, but can also behave as a halogen. H-3 (tritium) > He-3 + b.
2	He	helium	4.0026	4, 3	0		-268	0.1785 ×10^-3	Second most abundant element in the universe but scarce on earth. Produced underground by radioactive decay (a emission) of other elements. Used as a flotation agent in blimps and dirigibles, a gas-displacement medium for deep-sea diving, and as a supercoolant.
3	Li	lithium	6.939	7	1	179	1317	0.534	Reactive, silver-white metal; lightest of all metals.
4	Be	beryllium	9.0122	9	2	1278	2970	1.848	Lightweight, rigid, corrosion-resistant, steel-gray metal. Used as aerospace structural material, and as moderators and reflectors in nuclear reactors. Alloyed with Cu for use in springs and electrical contacts.
5	B	boron	10.811	11	3	2300	2550*	2.34	Soft brown non-metal, amorphous and crystalline allotropes. Used in abrasives, propellant mixtures, reactor control rods. *Sublimation point.
6	C	carbon	12.01115	11, 12, 13, 14	4, 3, 2	3500*	4827	1.8 - 3.53	Building block of all organic compounds. Four allotropes: graphite, lampblack, diamond, and buckminsterfullerene. N-14 + neutron > C-14 + proton. C-14 > N-14 + b, half-life 5730 yr. *Sublimation; no liquid phase.
7	N	nitrogen	14.0067	14	3, 5	-209.9	-195.8	1.25 ×10^-3	Most abundant element in earth's atmosphere (80%). Essential component of ammonia, amino acids, cyanides, and many other chemicals. In liquid form serves as a refrigerant.
8	O	oxygen	15.994	16	2	-218.4	-183.0	1.429 ×10^-3	Very electronegative gas. Most abundant element on earth's surface, present in rock, water (combined with numerous other elements), and in air as O₂ freed by photosynthesis in plants.
9	F	fluorine	18.9984	19	1	-220 -223	-188.1	1.108 (@bp)	Pale yellow gas. Most reactive halogen, most electronegative element; never found free in nature, but always in compounds, such as fluorite.
10	Ne	neon	20.183	20	0	-248.7	-246	0.9 ×10^-3	Colorless inert gas, glows red-orange in an electrical discharge. Trace amounts in atmosphere, used in lighting and display devices.
At.#	Sym.	Name	At.Wt.	Iso- topes	Val.	Melt (°C)	Boil (°C)	Sp.Gr.	Remarks
11	Na	sodium	22.99	23	1	97.8	892	0.971	Soft, light, silver white metal. Very reactive, found only in compounds; component of NaCl, table salt.
12	Mg	magnesium	24.312	24	2	649	1090	1.74 (@20°C)	Silver-white metal, burns with brilliant white flame. Occurs naturally only in compounds, such as minerals and salts.
13	Al	aluminum	26.98	27	3	660.2	2467	2.69	Ductile, silver-white metal. Ores in clays such as bauxite. Metal is good electrical and thermal conductor, forms non-shedding surface oxide, is used in applications requiring structural strength and light weight.
14	Si	silicon	28.086	28	4	1410	2355	2.33	Abundant (28% of earth crust) in form of SiO₂ and silicates: feldspar, mica, quartz, present in most rocks, sand, and soil. Used in building materials, glass, and semiconductors.
15	P	phosphorus	30.9738	31	3, 5	44.1	280	1.82	Reactive, toxic non-metal with 3 allotropes: white, red, and black. A key component of biochemistry. Occurs naturally in phosphates; used in fertilizers, detergents, matches, pesticides.
16	S	sulfur	32.064	32	2, 4, 6	112.8- 119.0	444.6	1.957 - 2.07	Allotropes: light yellow crystal, amorphous.
17	Cl	chlorine	35.45	35	1, 3, 5, 7	-101	-34.6	1.56 (@bp)	Yellow-green gas. Occurs naturally in compounds, such as NaCl, table salt.
18	Ar	argon	39.94	40	0	-189.2	-185.7	1.78 ×10^-3	Colorless inert gas comprises about 1% of earth's atmosphere. Used in incandescent bulbs, fluorescent and vacuum tubes, and in arc welding.
At.#	Sym.	Name	At.Wt.	Iso- topes	Val.	Melt (°C)	Boil (°C)	Sp.Gr.	Remarks
19	K	potassium	39.102	39, 40	1	63.65	774	0.862	Highly reactive, soft, silver-white metal. Its hydroxide and salts are used in soap and fertilizer. K-40 > Ar-40, half-life 1.3×10⁹ yr,
20	Ca	calcium	40.08	40	2	842- 848	1487	1.55	Moderately hard silver-white metal. Abundant (3% of earth crust) as CaCO₃ in limestone, gypsum, fluorite.
21	Sc	scandium	44.976	45	3	1540	2850	2.99	Silver-white metal, sometimes classified as a rare-earth element.
22	Ti	titanium	47.90	48	2, 3, 4	1660	3287	4.54	Light, corrosion-resistant, lustrous white metal. Brittle in its pure state, but makes strong alloys suitable for lightweight applications such as aircraft.
23	V	vanadium	50.942	51	2, 3, 4, 5	1890	3000	6.11	One of the hardest of all metals, with numerous applications in industry and tools.
24	Cr	chromium	51.996	52	2, 3, 6	1890	2482	7.18	Hard, tarnish- and corrosion-resistant, lustrous steel-gray metal. Its ore is chromite, FeCr₂O₃. Used in steel alloys and as decorative plating.
25	Mn	manganese	54.938	55	1, 2, 3, 4, 6, 7	1244	1962	7.21- 7.44	Gray-white metal. Used in ferromagnetic alloys.
26	Fe	iron	55.847	56	2, 3, 4, 6	1535	2750	7.874 (@20°C)	Strong, ductile, malleable, ferromagnetic silver-white metal. Moderately abundant ores include hematite and pyrite. Used in many applications, and the primary ingredient in steel.
27	Co	cobalt	58.9332	59, 60	2, 3	1495	2900	8.9	Hard, brittle metal. Used for magnetic alloys, and its salts are used in blue glass and ceramic pigments. Co-60 half-life 5.7 yr, used in industry and radiation therapy.
28	Ni	nickel	58.71	59	0, 1, 2, 3	1453	2732	8.902	Hard, brittle, ferromagnetic metal used for battery electrodes and electroplating.
29	Cu	copper	63.54	64	1, 2	1083	2595	8.96	Ductile red-brown metal, good electrical & thermal conductor. Used in wiring and plumbing. Also alloyed with Sn to produce bronze, and with Zn to produce brass.
30	Zn	zinc	65.37	65	2	419	907	7.133 (@25°C)	Brittle gray metal. Used in castings and electrodes, and also as a corrosion-inhibiting electroplated coating. Alloyed with Cu to make brass.
31	Ga	gallium	69.72	70	2, 3	29.78	2403	5.907	Rare, glue-gray metal, melts near room temperature. Used in semiconductor technology.
32	Ge	germanium	72.59	73	2, 4	937.4	2830	5.323 (@25°C)	Brittle, gray-white semimetal, used in semiconductors.
33	As	arsenic	74.922	75	3, 5	817*	613	5.73	Highly toxic semimetal with 3 allotropes: gray and black metallic forms, and a yellow nonmetal. Used in pesticides and as semiconductor doping agent. *No liquid phase at pressure < 28 atmospheres.
34	Se	selenium	78.96	79	2, 4, 6	217	684.9	4.28- 4.79	Semimetal, with several allotropes: black vitreous, red powder, red crystals, and lustrous gray crystals, similar to sulfur. Used in rectifiers and in xerography.
35	Br	bromine	79.904	80	1, 3, 5, 7	7.2	58.78	3.19	Dark brown, volatile liquid at room temperature, forms reddish gas. Used in gasoline anti-knock compounds, fumigants, and photographic chemicals.
36	Kr	krypton	83.80	84		-156.6	-152.3	3.73 ×10^-3	Whitish inert gas, used in gas-discharge and fluorescent lamps for exceptionally penetrating light.
At.#	Sym.	Name	At.Wt.	Iso- topes	Val.	Melt (°C)	Boil (°C)	Sp.Gr.	Remarks
37	Rb	rubidium	85.47	85, 87	1, 2, 3, 4	312K	961K	1.532	Soft, silver-white metal. Ignites spontaneously in air. Found in many minerals and mineral water, as well as in coffee, tea, tobacco, and other plants. Used in photocells. Rb-87 > Sr-87 + b, half-life 4.7×10¹⁰.
38	Sr	strontium	87.62	88, 85, 87, 90	2	769	1384	2.54	Silvery metal. Burns bright red, used in flares and fireworks. Sr-85 used to detect bone cancer; Sr-90 emits b, half-life 27 yr.
39	Y	yttrium	88.905	89	3	1522	3338	4.45 (@25°C)	Silvery metal, used to increase strength of Mg and Al alloys, and in color CRT phosphors.
40	Zr	zirconium	91.22	91	2, 3, 4	1852	3578	6.56 (@20°C)	Two allotropes: blue-black powder and soft, lustrous gray-white metal. Used in porcelain and alloys.
41	Nb	niobium / columbium	92.906	93	2, 3, 5	2468	4927	8.57	Soft, silvery metal, often found in ores with Ta. Used in arc welding, superconductor research, and as a component of stainless steel.
42	Mo	molybdenum	95.94	96	2, 3, 4, 5, 6	2617	4612	10.22 (@20°C)	Hard, silver-white metal, used in alloys, fertilizers, dyes, enamels, reagents.
43	Tc	technetium	99	90-111	0, 2, 4, 5, 6, 7	2200		11.50	First artificially created element (later found in nature in trace quantities). Tc-99 half-life 4.2×10⁶ yr.
44	Ru	ruthenium	101.07	101	0, 1, 2, 3, 4, 5, 6, 7, 8	2310	3900	12.41	Hard, acid-resistant white metal, used in hardened and superconducting alloys.
45	Rh	rhodium	102.905	103	2, 3, 4, 5, 6	1966	3727	12.41	Hard, durable, silver-white metal. Used in electroplating for a highly reflective and corrosion-resistant coating.
46	Pd	palladium	106.4	106	2, 3, 4	1552	3140	12.02 (@20°C)	Soft, steel-white, tarnish-resistant metal. Absorbs H. Used in electrical contacts, jewelry, watches, and surgical instruments.
47	Ag	silver	107.868	108	1, 2	960.8	2212	10.50	Malleable, lustrous white metal. Used in jewelry, tableware, photography, and alloy soldering.
48	Cd	cadmium	112.40	112	2	320.9	765	8.65	Soft, blue-white metal. Used in low-friction alloys, dental amalgams, Ni-Cd batteries, nuclear reactor shields, and rustproof electroplating.
49	In	indium	114.82	115	1, 2, 3	156.6	2000	7.31	Soft, malleable, silver-white metal, used in alloy bearings and reactor control rods.
50	Sn	tin	118.69	119	2, 4	231.9	2270	7.31	Malleable, silvery metal. Used to coat other metals, and as part of solder, pewter, type metal, and bronze.
51	Sb	antimony	121.75	122	3, 5	630.5	1380	6.691	Metal with 4 allotropes, most common of which is hard, brittle, lustrous silver-white crystalline substance. Used in alloys, ceramics, flame-proofing, paint, and storage batteries.
52	Te	tellurium	127.60	128	2, 4, 6	449.5	989.8	6.24	Brittle silver-white metal, used in alloys and ceramics.
53	I	iodine	126.904	127, 131	1, 3, 5, 7	113.5	184.35	4.93 (@20°C)	Toxic, gray-black or purple solid. Used as an antiseptic and in thyroid treatment.
54	Xe	xenon	131.30	131	0	-111.9	-107.1	5.887 ×10^-3	Once believed inert, forms some compounds. Used in stroboscopic and laser pumping lamps.
At.#	Sym.	Name	At.Wt.	Iso- topes	Val.	Melt (°C)	Boil (°C)	Sp.Gr.	Remarks
55	Cs	cesium	132.91	133, 137	1	28.5	690	1.87	Soft, silver-white metal, liquefies near room temperature. Most electropositive element, except for Fr. Used in photoelectric cells.
56	Ba	barium	137.34	137	2	725	1140	3.50	Soft, silver-white alkaline-earth metal. Its compounds are used in fireworks (BaNO₃), pesticides (BaCO₃), rubber products and paint (BaSO₄).
57	La	lanthanum	138.91	139	3	920	3469	5.98 - 6.186	Soft, silver-white rare-earth metal.
58	Ce	cerium	140.12	140	3, 4	795	3468	6.67 - 8.23	Lustrous iron-gray rare-earth metal.
59	Pr	praseodymium	140.98	141	3, 4	935	3127	6.8	Soft, silvery rare-earth metal.
60	Nd	neodymium	144.24	144	3	1024	3027	6.80 - 7.004	Bright, silvery rare-earth metal; allotropes.
61	Pm	promethium	145	141-154 (14)	3	1168	2460		Artificially created by U fission or neutron bombardment of Nd. Emits b.
62	Sm	samarium	150.35	150	2, 3	1072	1791	~7.50	Pale gray rare-earth metal.
63	Eu	europium	151.96	152	2, 3	826	1439	5.259	Soft, silvery rare-earth metal. Fluoresces red when struck by b, absorbs neutrons.
64	Gd	gadolinium	157.25	157	3	1312	~3000	7.8 - 7.896	Silver-white rare-earth metal.
65	Tb	terbium	158.925	159	3, 4	1356	3123	8.229	Soft, silver-gray rare-earth metal.
66	Dy	dysprosium	162.50	162	3	1407	2600	8.536	Soft, silvery rare-earth metal.
67	Ho	holmium	164.930	165	3	1461	2600	8.803	Stable, silvery rare-earth metal; highly paramagnetic.
68	Er	erbium	167.26	167	3	1497	2900	9.051	Soft, silvery rare-earth metal.
69	Tm	thulium	168.934	169	2, 3	1545	1727	9.3	Bright silver-gray rare-earth metal, used in portable X-ray machines.
70	Yb	ytterbium	173.04	173	2, 3	824	1196	6.54 - 6.972	Soft, bright silvery rare-earth metal use in portable irradiation devices.
71	Lu	lutetium	174.97	175	3	1663	3395	9.840 (@25°C)	Rare, silver-white rare-earth metal. Lu-? half-life 3×10¹⁰ yr. used for dating meteorites.
At.#	Sym.	Name	At.Wt.	Iso- topes	Val.	Melt (°C)	Boil (°C)	Sp.Gr.	Remarks
72	Hf	hafnium	178.49	178	4	2220	5400	13.3	Bright silver metal.
73	Ta	tantalum	180.948	181	2, 3, 4, 5	2996	5425	16.6	Very hard gray metal, resistant to chemical action below 150°C.
74	W	tungsten	183.85	184	2, 3, 4, 5, 6	3410	5900	19.3 (@20°C)	Highest melting point and lowest vapor pressure of any metal. Used in high-temperature applications, such as incandescent lamp filaments.
75	Re	rhenium	186.2	186	1, 2, 3, 4, 5, 6, 7	3180	5627	21.02	Very hard, highest melting point except for tungsten.
76	Os	osmium	190.2	190	2, 3, 4, 8	3000	5000	22.57	Hard, blue-white metal, the densest element. Used as a platinum hardener, and in pen points and instrument pivots.
77	Ir	iridium	192.2	192	3, 4	2410	4130	22.42	Very hard, brittle, corrosion-resistant, yellow-white metal, the second-densest element. Used in high-temperature materials, electrical contacts, and water-resistant bearings.
78	Pt	platinum	195.09	195	2, 3, 4	1772	3827	21.45	Rare, ductile, malleable, silver-white metal. Does not oxidize in air, and is one of few metals found free in nature. Used as catalyst and in electrical components, electroplating, dentistry, and jewelry.
79	Au	gold	196.967	197	1, 3	1063	2966	19.32	Rare, soft, very unreactive yellow metal, one of few found free in nature. Used in jewelry and electrical contacts.
80	Hg	mercury	200.59	201	1, 2	-38.87	356.58	13.546 (@20°C)	Toxic, shiny, silvery liquid metal. Usually found as a sulfide in cinnabar. Used in barometers, thermometers, vapor lamps, and batteries.
81	Tl	thallium	204.37	204	1, 3	303.5	1457	11.85	Soft, malleable, toxic metal used in photocells.
82	Pb	lead	207.19	204, 206, 207, 208	2, 4	327.5	1744	11.35	Soft, dense, toxic, blue-gray metal. Usually extracted from its sulfide galena. Used in storage batteries, radiation shields, weights, type metal, solder, bullets, and paint. U-238 > Pb-206; Ac > Pb-207; Th > Pb-208.
83	Bi	bismuth	208.980	209, 210, 214	3, 5	271.3	1560	9.747	Pinkish metal. Highly diamagnetic, poor electrical and thermal conductor. Expands on solidifying, so is useful in castings.
84	Po	polonium	209	192-218	2, 4	254	962	9.32	Naturally radioactive metal, produced by Ra decay, or by neutron bombardment of Bi or Pb. Po-210 emits a, half-life 138.39 da.
85	At	astatine	210	200-219	1, 3, 5, 7	302	337		Densest and most metal-like halogen. Naturally radioactive and very unstable. At-210 half-life 8.3 hr.
86	Rn	radon	222	222, 220, 219 (19)	0	-71	-61.8	9.9 ×10^-3 (gas) 4 (solid)	Naturally radioactive and densest noble gas, formed by decay, Ra-226 > Rn-222; Ac > Rn-219; Th > Rn-220. Rn-222 emits neutrons, half-life 3.82 da.
At.#	Sym.	Name	At.Wt.	Iso- topes	Val.	Melt (°C)	Boil (°C)	Sp.Gr.	Remarks
87	Fr	francium	223	(19)	1				Most electropositive alkali metal, probably liquid at room temperature. Fr-223 half-life 21 min.
88	Ra	radium	226	213-230 (13)	2	700	1737	6.0	Radioactive alkaline-earth metal. U > Ra-226. Ra-226 > Rn + a & neutron, half-life 1622 yr.
89	Ac	actinium	227	209-234	3	1050	~3200	10.07	U-235 > Ac-227; Th-232 > Ac-228. Ac-227 emits a, half-life 21.7 yr.
90	Th	thorium	232.038	212-236	4	1750	4500	11.7	Silver-white metal. Th-232 half-life 1.41x10¹⁰ yr.
91	Pa	protactinium	231	215-238					Pa-231 > Ac-227 + a, half-life 32480 yr.
92	U	uranium	238.029	238, 234, 235, 233, 237, 239	2, 3, 4, 5, 6	1132	3818	18.95	Toxic, silver-white metal. Used in research, nuclear fuel, nuclear weapons. U-238 > Pb-206 half-life 4.51x10⁹ yr. U-235 half-life 7.13x10⁸ yr.
93	Np	neptunium	237	228-242					Np-237 half-life 2.14x10⁶ yr.
94	Pu	plutonium	244	244, 239	3, 4, 5, 6	640	3235	19.84	Silvery metal. PU-239 used in nuclear fuel, nuclear weapons. Pu-244 half-life 7.6x10⁷ yr.
95	Am	americium	243	237-246	3, 4, 5, 6			11.7	Am-243 > a, half-life 7950 yr.
96	Cm	curium	247	247, 244 (13)	3	~1350			Silvery metal. Cm-247 half-life 1.64x10⁷ yr.
97	Bk	berkelium	247	242-251 (10)	3, 4	986			Bk-247 half-life 1380 yr.
98	Cf	californium	251	244-254					Cf-251 emits neutrons, half-life 800 yr.
99	Es	einsteinium	254	253-256		860			Es-254 half-life 276 da.
100	Fm	fermium	257	248-257 (10)					Fm-257 half-life 100 da.
101	Md	mendelevium	258	258, 256, 255					Md-256 half-life 1.5 hr.
102	No	nobelium	259	250-262					No-255 half-life 3 min.
103	Lr	lawrencium	260	255-260					Lr-260 half-life 3 min.
At.#	Sym.	Name	At.Wt.	Iso- topes	Val.	Melt (°C)	Boil (°C)	Sp.Gr.	Remarks

Cross-Reference Tables

Alphabetic by Name
Name	Sym.	At.#
actinium	Ac	89
aluminum	Al	13
americium	Am	95
antimony	Sb	51
argon	Ar	18
arsenic	As	33
astatine	At	85
barium	Ba	56
berkelium	Bk	97
beryllium	Be	4
bismuth	Bi	83
boron	B	5
bromine	Br	35
cadmium	Cd	48
calcium	Ca	20
californium	Cf	98
carbon	C	6
cerium	Ce	58
cesium	Cs	55
chlorine	Cl	17
chromium	Cr	24
Name	Sym.	At.#
cobalt	Co	27
copper	Cu	29
curium	Cm	96
dysprosium	Dy	66
erbium	Er	68
einsteinium	Es	99
europium	Eu	63
fermium	Fm	100
fluorine	F	9
francium	Fr	87
gallium	Ga	31
gadolinium	Gd	64
germanium	Ge	32
gold	Au	79
hafnium	Hf	72
helium	He	2
holmium	Ho	67
hydrogen	H	1
indium	In	49
iodine	I	53
iridium	Ir	77
Name	Sym.	At.#
iron	Fe	26
krypton	Kr	36
lanthanum	La	57
lawrencium	Lr	103
lead	Pb	82
lithium	Li	3
lutetium	Lu	71
magnesium	Mg	12
manganese	Mn	25
mendelevium	Md	101
mercury	Hg	80
molybdenum	Mo	42
neodymium	Nd	60
neon	Ne	10
neptunium	Np	93
nickel	Ni	28
niobium	Nb	41
nitrogen	N	7
nobelium	No	102
osmium	Os	76
oxygen	O	8
Name	Sym.	At.#
palladium	Pd	46
phosphorus	P	15
platinum	Pt	78
plutonium	Pu	94
polonium	Po	84
potassium	K	19
praseodymium	Pr	59
promethium	Pm	61
protactinium	Pa	91
radium	Ra	88
radon	Rn	86
rhenim	Re	75
rhodium	Rh	45
rubidium	Rb	37
ruthenium	Ru	44
samarium	Sm	62
scandium	Sc	21
selenium	Se	34
silicon	Si	14
silver	Ag	47
sodium	Na	11
Name	Sym.	At.#
strontium	Sr	38
sulfur	S	16
tantalum	Ta	73
technetium	Tc	43
tellurium	Te	52
terbium	Tb	65
thallium	Tl	81
thorium	Th	90
thulium	Tm	69
tin	Sn	50
titanium	Ti	22
tungsten	W	74
uranium	U	92
vanadium	V	23
xenon	Xe	54
ytterbium	Yb	70
yttrium	Y	39
zinc	Zn	30
zirconium	Zr	40
Name	Sym.	At.#
Alphabetic by Name

Alphabetic by Symbol
Sym.	Name	At.#
Ac	actinium	89
Ag	silver	47
Al	aluminum	13
Am	americium	95
Ar	argon	18
As	arsenic	33
At	astatine	85
Au	gold	79
B	boron	5
Ba	barium	56
Be	beryllium	4
Bi	bismuth	83
Bk	berkelium	97
Br	bromine	35
C	carbon	6
Ca	calcium	20
Cd	cadmium	48
Ce	cerium	58
Cf	californium	98
Cl	chlorine	17
Cm	curium	96
Sym.	Name	At.#
Co	cobalt	27
Cr	chromium	24
Cs	cesium	55
Cu	copper	29
Dy	dysprosium	66
Er	erbium	68
Es	einsteinium	99
Eu	europium	63
F	fluorine	9
Fe	iron	26
Fm	fermium	100
Fr	francium	87
Ga	gallium	31
Gd	gadolinium	64
Ge	germanium	32
H	hydrogen	1
He	helium	2
Hf	hafnium	72
Hg	mercury	80
Ho	holmium	67
I	iodine	53
Sym.	Name	At.#
In	indium	49
Ir	iridium	77
K	potassium	19
Kr	krypton	36
La	lanthanum	57
Li	lithium	3
Lr	lawrencium	103
Lu	lutetium	71
Md	mendelevium	101
Mg	magnesium	12
Mn	manganese	25
Mo	molybdenum	42
N	nitrogen	7
Na	sodium	11
Nb	niobium	41
Nd	neodymium	60
Ne	neon	10
Ni	nickel	28
No	nobelium	102
Np	neptunium	93
O	oxygen	8
Sym.	Name	At.#
Os	osmium	76
P	phosphorus	15
Pa	protactinium	91
Pb	lead	82
Pd	palladium	46
Pm	promethium	61
Po	polonium	84
Pr	praseodymium	59
Pt	platinum	78
Pu	plutonium	94
Ra	radium	88
Rb	rubidium	37
Re	rhenium	75
Rh	rhodium	45
Rn	radon	86
Ru	ruthenium	44
S	sulfur	16
Sb	antimony	51
Sc	scandium	21
Se	selenium	34
Si	silicon	14
Sym.	Name	At.#
Sm	samarium	62
Sn	tin	50
Sr	strontium	38
Ta	tantalum	73
Tb	terbium	65
Tc	technetium	43
Te	tellurium	52
Th	thorium	90
Ti	titanium	22
Tl	thallium	81
Tm	thulium	69
U	uranium	92
V	vanadium	23
W	tungsten	74
Xe	xenon	54
Y	yttrium	39
Yb	ytterbium	70
Zn	zinc	30
Zr	zirconium	40
Sym.	Name	At.#
Alphabetic by Symbol

Qualities of Major Element Groups
alkali metals	Ia	Highly electropositive elements, typical valence +1, metallic properties in solid phase, violently reactive with water.
alkaline earth metals	IIa	Strongly electropositive metals, typical valence +2.
transition metals	Ib - VIIIb	Includes most common metals, including the ferro-magnetic group.
lanthanide series	IIIb	A subgroup of transition metals, also classified as rare earths.
actinide series	IIIb	A subgroup of transition metals, also classified as rare earths.
other metals	IIIa - VIa	Weakly electropositive metals.
non-metals	IIIa - VIa	Non-metallic and semi-metallic solids, and gases, of reactivity ranging from slightly reducing to strongly oxidizing.
halogens	VIIa	Highly electronegative elements, typical valence -1, very toxic, range from solid to gaseous.
noble gases	0	Highly unreactive gases.
Many elements—even the lightest, hydrogen—have more than one isotope, and some of these may be radioactive. All known isotopes of technetium (43) and promethium (61), as well as all elements with atomic numbers greater than that of bismuth (83), are radioactive.