We remember from our school chemistry course that every element has its own specific atomic number. It is the same as the number of protons that the atom of each element has, so sometimes atomic number is called proton number. It is always the whole number and it ranges from 1 to 118, according to the number of the element in the Periodic Table. This number can be really important and something essential to know, in relation to a certain chemical element which is the issue of our interest at the moment.
Why is this so? Why is the atomic number so important? First of all, it is the number that makes elements different from one another as it shows the number of protons in their nuclei. Also, knowing the atomic number of an element can give us an idea about the position of the element in the Periodic Table. Atomic number of an element never changes: for example, the atomic number of oxygen is always 8, and the atomic number of Chlorine is always 18. The atomic number is marked with the symbol Z, taken from a German word zahl (or atomzahl, which is 'atomic number' in German).
This website is created for those who need to know the atomic number of a central chemical element. By using our website, you can do it in just one click and receive short and correct information on this matter. There is also some extra summary on every each chemical element which can be found at our website, including the atomic weight of each element, as well as physical and chemical properties of every element and its importance. Use this website at any time when you need to get fast and precise information about atomic or proton number of chemical elements.
List of chemical elements in periodic table with atomic number, chemical symbol and atomic weight. You can sort the elements by clicking on the table headers. Please click on the element name for complete list of element properties.
- Symbol: Cs; Atomic number: 55; Relative atomic mass (A r): 16 (6) Standard state: solid at 298 K (but melts only slightly above this temperature) Appearance: silvery gold; Classification: Metallic.
- Symbol: Cs Atomic Number: 55 Atomic Mass: 132.90546 amu Melting Point: 28.5 °C (301.65 K, 83.3 °F) Boiling Point: 678.4 °C (951.55005 K, 1253.12 °F) Number of Protons/Electrons: 55 Number of Neutrons: 78 Classification: Alkali Metal Crystal Structure: Cubic Density @ 293 K: 1.873 g/cm 3 Color: silver British Spelling: Caesium IUPAC Spelling: Caesium Atomic Structure.
- Cesium Cs 137 is a radioactive isotope of cesium with an atomic mass of 139 and potential application in radiotherapy. Cesium Cs 137 is prevalent due to its spontaneous production, which occurs as a result of nuclear fission of other radioactive materials, such as uranium and plutonium.
- This is a list of the 118 chemical elements which have been identified as of 2021. A chemical element, often simply called an element, is a species of atoms which all have the same number of protons in their atomic nuclei (i.e., the same atomic number, or Z).
The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present). The number of protons determines how many electrons surround the nucleus, and it is the arrangement of these electrons that.
Atomic Number | Chemical Symbol | Element Name | Atomic Weight (u) |
---|---|---|---|
1 | H | Hydrogen | 1.008 |
2 | He | Helium | 4.003 |
3 | Li | Lithium | 6.94 |
4 | Be | Beryllium | 9.012 |
5 | B | Boron | 10.81 |
6 | C | Carbon | 12.011 |
7 | N | Nitrogen | 14.007 |
8 | O | Oxygen | 15.999 |
9 | F | Fluorine | 18.998 |
10 | Ne | Neon | 20.18 |
11 | Na | Sodium | 22.99 |
12 | Mg | Magnesium | 24.305 |
13 | Al | Aluminium | 26.982 |
14 | Si | Silicon | 28.085 |
15 | P | Phosphorus | 30.974 |
16 | S | Sulfur | 32.06 |
17 | Cl | Chlorine | 35.45 |
18 | Ar | Argon | 39.948 |
19 | K | Potassium | 39.098 |
20 | Ca | Calcium | 40.078 |
21 | Sc | Scandium | 44.956 |
22 | Ti | Titanium | 47.867 |
23 | V | Vanadium | 50.942 |
24 | Cr | Chromium | 51.996 |
25 | Mn | Manganese | 54.938 |
26 | Fe | Iron | 55.845 |
27 | Co | Cobalt | 58.933 |
28 | Ni | Nickel | 58.693 |
29 | Cu | Copper | 63.546 |
30 | Zn | Zinc | 65.38 |
31 | Ga | Gallium | 69.723 |
32 | Ge | Germanium | 72.63 |
33 | As | Arsenic | 74.922 |
34 | Se | Selenium | 78.971 |
35 | Br | Bromine | 79.904 |
36 | Kr | Krypton | 83.798 |
37 | Rb | Rubidium | 85.468 |
38 | Sr | Strontium | 87.62 |
39 | Y | Yttrium | 88.906 |
40 | Zr | Zirconium | 91.224 |
41 | Nb | Niobium | 92.906 |
42 | Mo | Molybdenum | 95.95 |
43 | Tc | Technetium | 98 |
44 | Ru | Ruthenium | 101.07 |
45 | Rh | Rhodium | 102.906 |
46 | Pd | Palladium | 106.42 |
47 | Ag | Silver | 107.868 |
48 | Cd | Cadmium | 112.414 |
49 | In | Indium | 114.818 |
50 | Sn | Tin | 118.71 |
51 | Sb | Antimony | 121.76 |
52 | Te | Tellurium | 127.6 |
53 | I | Iodine | 126.904 |
54 | Xe | Xenon | 131.293 |
55 | Cs | Caesium | 132.905 |
56 | Ba | Barium | 137.327 |
57 | La | Lanthanum | 138.905 |
58 | Ce | Cerium | 140.116 |
59 | Pr | Praseodymium | 140.908 |
60 | Nd | Neodymium | 144.242 |
61 | Pm | Promethium | 145 |
62 | Sm | Samarium | 150.36 |
63 | Eu | Europium | 151.964 |
64 | Gd | Gadolinium | 157.25 |
65 | Tb | Terbium | 158.925 |
66 | Dy | Dysprosium | 162.5 |
67 | Ho | Holmium | 164.93 |
68 | Er | Erbium | 167.259 |
69 | Tm | Thulium | 168.934 |
70 | Yb | Ytterbium | 173.045 |
71 | Lu | Lutetium | 174.967 |
72 | Hf | Hafnium | 178.49 |
73 | Ta | Tantalum | 180.948 |
74 | W | Tungsten | 183.84 |
75 | Re | Rhenium | 186.207 |
76 | Os | Osmium | 190.23 |
77 | Ir | Iridium | 192.217 |
78 | Pt | Platinum | 195.084 |
79 | Au | Gold | 196.967 |
80 | Hg | Mercury | 200.592 |
81 | Tl | Thallium | 204.38 |
82 | Pb | Lead | 207.2 |
83 | Bi | Bismuth | 208.98 |
84 | Po | Polonium | 209 |
85 | At | Astatine | 210 |
86 | Rn | Radon | 222 |
87 | Fr | Francium | 223 |
88 | Ra | Radium | 226 |
89 | Ac | Actinium | 227 |
90 | Th | Thorium | 232.038 |
91 | Pa | Protactinium | 231.036 |
92 | U | Uranium | 238.029 |
93 | Np | Neptunium | 237 |
94 | Pu | Plutonium | 244 |
95 | Am | Americium | 243 |
96 | Cm | Curium | 247 |
97 | Bk | Berkelium | 247 |
98 | Cf | Californium | 251 |
99 | Es | Einsteinium | 252 |
100 | Fm | Fermium | 257 |
101 | Md | Mendelevium | 258 |
102 | No | Nobelium | 259 |
103 | Lr | Lawrencium | 266 |
104 | Rf | Rutherfordium | 267 |
105 | Db | Dubnium | 268 |
106 | Sg | Seaborgium | 269 |
107 | Bh | Bohrium | 270 |
108 | Hs | Hassium | 277 |
109 | Mt | Meitnerium | 278 |
110 | Ds | Darmstadtium | 281 |
111 | Rg | Roentgenium | 282 |
112 | Cn | Copernicium | 285 |
113 | Nh | Nihonium | 286 |
114 | Fl | Flerovium | 289 |
115 | Mc | Moscovium | 290 |
116 | Lv | Livermorium | 293 |
117 | Ts | Tennessine | 294 |
118 | Og | Oganesson | 294 |
Lists of Elements in Periodic Table
What Is Ca Atomic Number
You can also list the elements in various ordered properties with printable tables below.
Lists of Elements by Group Number in Periodic Table
» Group 1» Group 2» Group 3» Group 4» Group 5» Group 6» Group 7» Group 8» Group 9» Group 10» Group 11» Group 12» Group 13» Group 14» Group 15» Group 16» Group 17» Group 18Cs Chemistry Element
In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present). The number of protons determines how many electrons surround the nucleus, and it is the arrangement of these electrons that determines most of the chemical behavior of an element.
In a periodic table arranged in order of increasing atomic number, elements having similar chemical properties naturally line up in the same column (group). For instance, all of the elements in Group 1A are relatively soft metals, react violently with water, and form 1+ charges; all of the elements in Group 8A are unreactive, monatomic gases at room temperature, etc. In other words, there is a periodic repetition of the properties of the chemical elements with increasing mass.
Cs 137 Atomic Number
In the original periodic table published by Dimitri Mendeleev in 1869, the elements were arranged according to increasing atomic mass— at that time, the nucleus had not yet been discovered, and there was no understanding at all of the interior structure of the atom, so atomic mass was the only guide to use. Once the structure of the nucleus was understood, it became clear that it was the atomic number that governed the properties of the elements.