Atomic Number

Atomic Number 117
Atomic Number Of Iron
Atomic Number 8

The elements of the periodic table sorted by atomic number

click on any elements name for further chemical properties, environmental data or health effects.

Atomic number, chemical symbol, and mass number. Carbon has an atomic number of six, and two stable isotopes with mass numbers of twelve and thirteen, respectively. Its average atomic mass is 12.11. Scientists determine the atomic mass by calculating the mean of the mass numbers for its naturally-occurring isotopes. Often, the resulting number. The atomic number is the number of protons in an atom, and isotopes have the same atomic number but differ in the number of neutrons. If you're seeing this message, it means we're having trouble loading external resources on our website.

This list contains the 118 elements of chemistry.

The chemical elements of the periodic chart sorted by:	Atomic number	Name chemical element	Symbol
- Name alphabetically	1	Hydrogen	H
- Atomic number	2	Helium	He
- Symbol	3	Lithium	Li
- Atomic Mass	4	Beryllium	Be
- Electronegativity	5	Boron	B
- Density	6	Carbon	C
- Melting point	7	Nitrogen	N
- Boiling point	8	Oxygen	O
- Vanderwaals radius	9	Fluorine	F
- Year of discovery	10	Neon	Ne
- Inventor surname	11	Sodium	Na
- Elements in earthcrust	12	Magnesium	Mg
- Elements in human body	13	Aluminum	Al
- Covalenz radius	14	Silicon	Si
- Ionization energy	15	Phosphorus	P
For chemistry students and teachers: The tabular chart on the right is arranged by Atomic number. The first chemical element is Hydrogen and the last is Ununoctium. Please note that the elements do not show their natural relation towards each other as in the Periodic system. There you can find the metals, semi-conductor(s), non-metal(s), inert noble gas(ses), Halogens, Lanthanoides, Actinoids (rare earth elements) and transition metals.	16	Sulfur	S
	17	Chlorine	Cl
	18	Argon	Ar
	19	Potassium	K
	20	Calcium	Ca
	21	Scandium	Sc
	22	Titanium	Ti
	23	Vanadium	V
	24	Chromium	Cr
	25	Manganese	Mn
	26	Iron	Fe
	27	Cobalt	Co
	28	Nickel	Ni
	29	Copper	Cu
	30	Zinc	Zn
	31	Gallium	Ga
	32	Germanium	Ge
	33	Arsenic	As
	34	Selenium	Se
	35	Bromine	Br
	36	Krypton	Kr
37	Rubidium	Rb
38	Strontium	Sr
39	Yttrium	Y
40	Zirconium	Zr
41	Niobium	Nb
42	Molybdenum	Mo
43	Technetium	Tc
44	Ruthenium	Ru
45	Rhodium	Rh
46	Palladium	Pd
47	Silver	Ag
48	Cadmium	Cd
49	Indium	In
50	Tin	Sn
51	Antimony	Sb
52	Tellurium	Te
53	Iodine	I
54	Xenon	Xe
55	Cesium	Cs
56	Barium	Ba
57	Lanthanum	La
58	Cerium	Ce
59	Praseodymium	Pr
60	Neodymium	Nd
61	Promethium	Pm
62	Samarium	Sm
63	Europium	Eu
64	Gadolinium	Gd
65	Terbium	Tb
66	Dysprosium	Dy
67	Holmium	Ho
68	Erbium	Er
69	Thulium	Tm
70	Ytterbium	Yb
71	Lutetium	Lu
72	Hafnium	Hf
73	Tantalum	Ta
74	Tungsten	W
75	Rhenium	Re
76	Osmium	Os
77	Iridium	Ir
78	Platinum	Pt
79	Gold	Au
80	Mercury	Hg
81	Thallium	Tl
82	Lead	Pb
83	Bismuth	Bi
84	Polonium	Po
85	Astatine	At
86	Radon	Rn
87	Francium	Fr
88	Radium	Ra
89	Actinium	Ac
90	Thorium	Th
91	Protactinium	Pa
92	Uranium	U
93	Neptunium	Np
94	Plutonium	Pu
95	Americium	Am
96	Curium	Cm
97	Berkelium	Bk
98	Californium	Cf
99	Einsteinium	Es
100	Fermium	Fm
101	Mendelevium	Md
102	Nobelium	No
103	Lawrencium	Lr
104	Rutherfordium	Rf
105	Dubnium	Db
106	Seaborgium	Sg
107	Bohrium	Bh
108	Hassium	Hs
109	Meitnerium	Mt
110	Darmstadtium	Ds
111	Roentgenium	Rg
112	Copernicium	Cn
113	Nihonium	Nh
114	Flerovium	Fl
115	Moscovium	Mc
116	Livermorium	Lv
117	Tennessine	Ts
118	Oganesson	Og

Click here: for a schematic overview of the periodic table of elements in chart form

Do you need to know the weight of some molecules? Try our Molecular Weight Calculator!

Please report any accidental mistake in the above statistics on chemical elements

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Learning Objective

Determine the relationship between the mass number of an atom, its atomic number, its atomic mass, and its number of subatomic particles

Key Points

Atomic Number 117

Neutral atoms of each element contain an equal number of protons and electrons.
The number of protons determines an element’s atomic number and is used to distinguish one element from another.
The number of neutrons is variable, resulting in isotopes, which are different forms of the same atom that vary only in the number of neutrons they possess.
Together, the number of protons and the number of neutrons determine an element’s mass number.
Since an element’s isotopes have slightly different mass numbers, the atomic mass is calculated by obtaining the mean of the mass numbers for its isotopes.

Terms

atomic massThe average mass of an atom, taking into account all its naturally occurring isotopes.
mass numberThe sum of the number of protons and the number of neutrons in an atom.
atomic numberThe number of protons in an atom.

Atomic Number

Neutral atoms of an element contain an equal number of protons and electrons. The number of protons determines an element’s atomic number (Z) and distinguishes one element from another. For example, carbon’s atomic number (Z) is 6 because it has 6 protons. The number of neutrons can vary to produce isotopes, which are atoms of the same element that have different numbers of neutrons. The number of electrons can also be different in atoms of the same element, thus producing ions (charged atoms). For instance, iron, Fe, can exist in its neutral state, or in the +2 and +3 ionic states.

Mass Number

Atomic Number Of Iron

An element’s mass number (A) is the sum of the number of protons and the number of neutrons. The small contribution of mass from electrons is disregarded in calculating the mass number. This approximation of mass can be used to easily calculate how many neutrons an element has by simply subtracting the number of protons from the mass number. Protons and neutrons both weigh about one atomic mass unit or amu. Isotopes of the same element will have the same atomic number but different mass numbers.

Scientists determine the atomic mass by calculating the mean of the mass numbers for its naturally-occurring isotopes. Often, the resulting number contains a decimal. For example, the atomic mass of chlorine (Cl) is 35.45 amu because chlorine is composed of several isotopes, some (the majority) with an atomic mass of 35 amu (17 protons and 18 neutrons) and some with an atomic mass of 37 amu (17 protons and 20 neutrons).

Given an atomic number (Z) and mass number (A), you can find the number of protons, neutrons, and electrons in a neutral atom. For example, a lithium atom (Z=3, A=7 amu) contains three protons (found from Z), three electrons (as the number of protons is equal to the number of electrons in an atom), and four neutrons (7 – 3 = 4).

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http://www.boundless.com/
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Atomic Number 8

http://en.wiktionary.org/wiki/atomic_number
Wiktionary
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http://www.boundless.com//biology/definition/atomic-mass–2
Boundless Learning
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“A-level Chemistry/OCR/Atoms, Bonds and Groups/Atoms and Reactions/Atoms.”

http://en.wikibooks.org/wiki/A-level_Chemistry/OCR/Atoms,_Bonds_and_Groups/Atoms_and_Reactions/Atoms
Wikibooks
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http://cnx.org/content/m44390/latest/?collection=col11448/latest
OpenStax CNX
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