Periodic table

The **periodic table** is a table that puts all known chemical elements in a specific order. Elements that have similar characteristics are often put near each other.  In the table, the elements are placed in the order of their atomic numbers starting with the lowest number of one, hydrogen. The atomic number of an element is the same as the number of protons in that particular nucleus of an atom. In the  table the elements are arranged into _periods_ and _group._ A row of elements across the table is called a _period_. Each period has a number; from 1 to 8. Period 1 has only 2 elements in it: hydrogen and helium. Period 2 and Period 3 both have 8 elements. Other periods are longer. Elements in a period have consecutive atomic numbers.

The periodic classification of elements offers a systematic approach to organizing and studying the universe's vast array of elements. This method is crucial for comprehending the chemistry of elements and their compounds. By grouping elements with similar properties, scientists uncover patterns and trends in these fundamental building blocks of matter. **Read more ...**

A column of elements down the table is called a _group_. There are 18 groups in the standard periodic table.  Each group has a number: from 1 to 18. Elements in a group have electrons arranged in similar ways, according to the number of valency electrons, which gives them similar chemical properties (they behave in similar ways).  For example, group 18 is known as the noble gases because they are all gases and they do not combine with other atoms. **Read more ...**

There are two systems of group numbers; one using Arabic numerals (1, 2, 3) and the other using Roman numerals (I, II, III). The Roman numeral names were used in most of the 20th century.  In 1990 the International Union of Pure and Applied Chemistry (IUPAC) decided to use the new system with Arabic numerals, to replace the two old group systems that used Roman numerals.

- The periodic classification of elements is a systematic way of organizing elements based on their chemical and physical properties.
- Understanding the periodic table and its patterns helps predict the behavior and reactivity of elements.
- Mendeleev's periodic table and the modern periodic table are two important milestones in the classification of elements.
- Periodic trends, such as atomic size, valency, and electronegativity, can be observed within the periodic table. **Read more ...**

The periodic table was invented by the Russian chemist Dmitry Ivanovich Mendeleyev (18341907). In his honor, element 101 was named after him, mendelevium.

## Standard periodic table

|**Group** →|**1**|**2**|**3**|**4**|**5**|**6**|**7**|**8**|**9**|**10**|**11**|**12**|**13**|**14**|**15**|**16**|**17**|**18**|||||||||||||||||||
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|**Period** ↓|colspan="20"||||||||||||||||||||||||||||||||||||
|**1**|style="background-color:#a0ffa0;color:blue;border:1px solid black;"|1 H Hydrogen|colspan="16"||style="background-color:#c0ffff;color:blue;border:1px solid black;"|2 He Helium|||||||||||||||||||||||||||||||
|**2**|style="background-color:#f66;border:1px solid black;"|3 Li Lithium|style="background-color:#ffdead;border:1px solid black;"|4 Be Beryllium|colspan="10"||style="background-color:#cc9;border:1px solid black;"|5 B Boron|style="background-color:#a0ffa0;border:1px solid black;"|6 C Carbon|style="background-color:#a0ffa0;color:blue;border:1px solid black;"|7 N Nitrogen|style="background-color:#a0ffa0;color:blue;border:1px solid black;"|8 O Oxygen|style="background-color:#ff9;color:blue;border:1px solid black;"|9 F Fluorine|style="background-color:#c0ffff;color:blue;border:1px solid black;"|10 Ne Neon|||||||||||||||||||
|**3**|style="background-color:#f66;border:1px solid black;"|11 Na Sodium|style="background-color:#ffdead;border:1px solid black;"|12 Mg Magnesium|colspan="10"||style="background-color:#ccc;border:1px solid black;"|13 Al Aluminium|style="background-color:#cc9;border:1px solid black;"|14 Si Silicon|style="background-color:#a0ffa0;border:1px solid black;"|15 P Phosphorus|style="background-color:#a0ffa0;border:1px solid black;"|16 S Sulfur|style="background-color:#ff9;color:blue;border:1px solid black;"|17 Cl Chlorine|style="background-color:#c0ffff;color:blue;border:1px solid black;"|18 Ar Argon|||||||||||||||||||
|**4**|style="background-color:#f66;border:1px solid black;"|19 K Potassium|style="background-color:#ffdead;border:1px solid black;"|20 Ca Calcium|style="background-color:#ffc0c0;border:1px solid black;"|21 Sc Scandium|style="background-color:#ffc0c0;border:1px solid black;"|22 Ti Titanium|style="background-color:#ffc0c0;border:1px solid black;"|23 V Vanadium|style="background-color:#ffc0c0;border:1px solid black;"|24 Cr Chromium|style="background-color:#ffc0c0;border:1px solid black;"|25 Mn Manganese|style="background-color:#ffc0c0;border:1px solid black;"|26 Fe Iron|style="background-color:#ffc0c0;border:1px solid black;"|27 Co Cobalt|style="background-color:#ffc0c0;border:1px solid black;"|28 Ni Nickel|style="background-color:#ffc0c0;border:1px solid black;"|29 Cu Copper|style="background-color:#ffc0c0;border:1px solid black;"|30 Zn Zinc|style="background-color:#ccc;border:1px solid black;"|31 Ga Gallium|style="background-color:#cc9;border:1px solid black;"|32 Ge Germanium|style="background-color:#cc9;border:1px solid black;"|33 As Arsenic|style="background-color:#a0ffa0;border:1px solid black;"|34 Se Selenium|style="background-color:#ff9;color:green;border:1px solid black;"|35 Br Bromine|style="background-color:#c0ffff;color:blue;border:1px solid black;"|36 Kr Krypton|
|**5**|style="background-color:#f66;border:1px solid black;"|37 Rb Rubidium|style="background-color:#ffdead;border:1px solid black;"|38 Sr Strontium|style="background-color:#ffc0c0;border:1px solid black;"|39 Y Yttrium|style="background-color:#ffc0c0;border:1px solid black;"|40 Zr Zirconium|style="background-color:#ffc0c0;border:1px solid black;"|41 Nb Niobium|style="background-color:#ffc0c0;border:1px solid black;"|42 Mo Molybdenum|style="background-color:#ffc0c0;border:1px dashed black;"|43 Tc Technetium|style="background-color:#ffc0c0;border:1px solid black;"|44 Ru Ruthenium|style="background-color:#ffc0c0;border:1px solid black;"|45 Rh Rhodium|style="background-color:#ffc0c0;border:1px solid black;"|46 Pd Palladium|style="background-color:#ffc0c0;border:1px solid black;"|47 Ag Silver|style="background-color:#ffc0c0;border:1px solid black;"|48 Cd Cadmium|style="background-color:#ccc;border:1px solid black;"|49 In Indium|style="background-color:#ccc;border:1px solid black;"|50 Sn Tin|style="background-color:#cc9;border:1px solid black;"|51 Sb Antimony|style="background-color:#cc9;border:1px solid black;"|52 Te Tellurium|style="background-color:#ff9;border:1px solid black;"|53 I Iodine|style="background-color:#c0ffff;color:blue;border:1px solid black;"|54 Xe Xenon|
|**6**|style="background-color:#f66;border:1px solid black;"|55 Cs Cesium|style="background-color:#ffdead;border:1px solid black;"|56 Ba Barium|style="vertical-align: top; background-color:#ffbfff;1px;"|* Lanthanides|style="background-color:#ffc0c0;border:1px solid black;"|72 Hf Hafnium|style="background-color:#ffc0c0;border:1px solid black;"|73 Ta Tantalum|style="background-color:#ffc0c0;border:1px solid black;"|74 W Tungsten|style="background-color:#ffc0c0;border:1px solid black;"|75 Re Rhenium|style="background-color:#ffc0c0;border:1px solid black;"|76 Os Osmium|style="background-color:#ffc0c0;border:1px solid black;"|77 Ir Iridium|style="background-color:#ffc0c0;border:1px solid black;"|78 Pt Platinum|style="background-color:#ffc0c0;border:1px solid black;"|79 Au Gold </td>|style="background-color:#ffc0c0;color:green;border:1px solid black;"|80 Hg Mercury|style="background-color:#ccc;border:1px solid black;"|81 Tl Thallium|style="background-color:#ccc;border:1px solid black;"|82 Pb Lead|style="background-color:#ccc;border:1px dashed black;"|83 Bi Bismuth|style="background-color:#cc9;border:1px dashed black;"|84 Po Polonium|style="background-color:#ff9;border:1px dashed black;"|85 At Astatine|style="background-color:#c0ffff;color:black;border:1px dashed black;"|86 Rn Radon|
|**7**|style="background-color:#f66;border:1px dashed black;"|87  Fr Francium|style="background-color:#ffdead;border:1px dashed black;"|88 Ra Radium|style="vertical-align: top; background-color:#f9c;1px;"|** Actinides|style="background-color:#ffc0c0;border:1px dotted black;"|104 Rf Rutherfordium|style="background-color:#ffc0c0;border:1px dotted black;"|105 Db Dubnium|style="background-color:#ffc0c0;border:1px dotted black;"|106 Sg Seaborgium|style="background-color:#ffc0c0;border:1px dotted black;"|107 Bh Bohrium|style="background-color:#ffc0c0;border:1px dotted black;"|108 Hs Hassium|style="background-color:#ffc0c0;border:1px dotted black;"|109 Mt Meitnerium|style="background-color:#ffc0c0;border:1px dotted black;"|110 Ds Darmstadtium|style="background-color:#ffc0c0;border:1px dotted black;"|111 Rg Roentgenium|style="background-color:#ffc0c0;border:1px dotted black;"|112 Cn Copernicium|style="background-color:#ccc;color:green;border:1px dotted black;"|113 Nh Nihonium|style="background-color:#ccc;border:1px dotted black;"|114 Fl Flerovium|style="background-color:#ccc;color:green;border:1px dotted black;"|115 Mc Moscovium|style="background-color:#ccc;border:1px dotted black;"|116 Lv Livermorium|style="background-color:#ff9;border:1px dotted black;"|117 Ts Tennessine|style="background-color:#c0ffff;border:1px dotted black;"|118 Og Oganesson|
|colspan="4" style="text-align:right"|* **Lanthanide Series**|style="background-color:#ffbfff;border:1px solid black;"|57 La Lanthanum|style="background-color:#ffbfff;border:1px solid black;"|58 Ce Cerium|style="background-color:#ffbfff;border:1px solid black;"|59 Pr Praseodymium|style="background-color:#ffbfff;border:1px solid black;"|60 Nd Neodymium|style="background-color:#ffbfff;border:1px dashed black;"|61 Pm Promethium|style="background-color:#ffbfff;border:1px solid black;"|62 Sm Samarium|style="background-color:#ffbfff;border:1px solid black;"|63 Eu Europium|style="background-color:#ffbfff;border:1px solid black;"|64 Gd Gadolinium|style="background-color:#ffbfff;border:1px solid black;"|65 Tb Terbium|style="background-color:#ffbfff;border:1px solid black;"|66 Dy Dysprosium|style="background-color:#ffbfff;border:1px solid black;"|67 Ho Holmium|style="background-color:#ffbfff;border:1px solid black;"|68 Er Erbium|style="background-color:#ffbfff;border:1px solid black;"|69 Tm Thulium|style="background-color:#ffbfff;border:1px solid black;"|70 Yb Ytterbium|style="background-color:#ffbfff;border:1px solid black;"|71 Lu Lutetium||||||
|colspan="4" style="text-align:right"|** **Actinide Series**|style="background-color:#f9c;border:1px dashed black;"|89 Ac Actinium|style="background-color:#f9c;border:1px dashed black;"|90 Th Thorium|style="background-color:#f9c;border:1px dashed black;"|91 Pa Protactinium|style="background-color:#f9c;border:1px dashed black;"|92 U Uranium|style="background-color:#f9c;border:1px dashed black;"|93 Np Neptunium|style="background-color:#f9c;border:1px dashed black;"|94 Pu Plutonium|style="background-color:#f9c;border:1px dotted black;"|95 Am Americium|style="background-color:#f9c;border:1px dotted black;"|96 Cm Curium|style="background-color:#f9c;border:1px dotted black;"|97 Bk Berkelium|style="background-color:#f9c;border:1px dotted black;"|98 Cf Californium|style="background-color:#f9c;border:1px dotted black;"|99 Es Einsteinium|style="background-color:#f9c;border:1px dotted black;"|100 Fm Fermium|style="background-color:#f9c;border:1px dotted black;"|101 Md Mendelevium|style="background-color:#f9c;border:1px dotted black;"|102 No Nobelium|style="background-color:#f9c;border:1px dotted black;"|103 Lr Lawrencium||||||

- Chemical Series of the Periodic Table

- <div style="background-color:#f66">Alkali metals</div>
- <div style="background-color:#ffdead">Alkaline earths</div>
- <div style="background-color:#ffbfff">Lanthanides</div>
- <div style="background-color:#f9c">Actinides</div>
- <div style="background-color:#ffc0c0">Transition metals</div>
- <div style="background-color:#ccc">Poor metals</div>
- <div style="background-color:#cc9">Metalloids/Semi metals/Half metals</div>
- <div style="background-color:#a0ffa0">Nonmetals</div>
- <div style="background-color:#ff9">Halogens</div>
- <div style="background-color:#c0ffff">Noble gases</div>

- State at standard temperature and pressure. The color of the number (atomic number) above the element symbol shows the state of the element at normal conditions.
- those in <span style="color:blue;">blue</span> are gases,
- those in <span style="color:green;">green</span> are liquids,
- and those in <span style="color:black;">black</span> are solids.

- Radioactivity

- <div style="border:solid 1px black;padding:1px;">Those with solid borders have stable isotopes (Primordial Elements)</div>
- <div style="border:dashed 1px black;padding:1px;">Those with dashed borders have only radioactive naturally occurring isotopes</div>
- <div style="border:dotted 1px black;padding:1px;">Those with dotted borders do not occur naturally (Synthetic Elements)</div>

## Other arrangements of the Periodic Table

The version of the periodic table shown above is the one most used.  Other widespread versions are shown below:

## Other versions

- The standard table provides the basics. It is shown above
- A vertical table for improved readability in web browsers
- The big table provides the basics plus full element names
- The huge table provides the basics plus full element names and atomic masses
- Electron configurations
- Metals and Non Metals
- List of elements: includes name, symbol, atomic number, atomic mass, group, and period; sortable by any of those
- List of elements by symbol
- List of elements by boiling point
- List of elements by melting point
- List of elements by density
- Class 10 notes Periodic Classification

## Related pages

- Periodic table group
- Periodic table period
- Extended periodic table

## Other websites

- Periodic Table of the Elements – displays basic properties
- WebElements Periodic table