Periodic Table of Elements (Interactive, All 118)

The full periodic table

Here is the complete chart of the full periodic table elements, from hydrogen to oganesson. The two rows printed below the main body are the lanthanides and actinides. They really belong inside periods 6 and 7, but placing them inside would make the chart too wide for a page or a phone screen.

Want this on paper? The periodic table PDF page has colour, black and white, blank practice and configuration versions in A4 size, and a chart with Hindi names is in periodic table in Hindi.

How to read one box of the periodic table

Every element gets one small box, and each box carries the same four facts in the same places. Once you can read one box, you can read the whole chart.

• Atomic number (Z), usually in the top corner. It is the number of protons in the nucleus, and in a neutral atom it also equals the number of electrons. No two elements share a Z.
• Symbol, the big letters in the middle: one capital letter, or a capital followed by a small letter (Co is cobalt, but CO is carbon monoxide, a compound).
• Name of the element, written under the symbol.
• Atomic mass in u (unified atomic mass units), the average mass of the atoms as found in nature. A value in square brackets, like [294], is used for an element too short lived to have a natural average; it shows the mass number of its most stable known isotope.

The tool above adds more: the electronic configuration, electrons per shell, group, period, block and valency. For a full list of masses, see atomic mass of elements.

Groups and periods: columns and rows

A group is a vertical column. There are 18, numbered 1 to 18 from left to right. Elements in one group have the same number of valence electrons (outer shell electrons), so they react in similar ways. Sodium and potassium, both in group 1, each have one outer electron and both react vigorously with water.

A period is a horizontal row. There are 7. The period number tells you how many shells an atom has. Sodium is in period 3, so its electrons sit in three shells: 2, 8, 1.

Some groups have family names you will hear often: group 1 is the alkali metals, group 2 the alkaline earth metals, group 17 the halogens and group 18 the noble gases. The modern periodic table page explains why the period lengths come out as 2, 8, 8, 18, 18, 32, 32.

The four blocks: s, p, d and f

The chart also splits into four blocks, named after the subshell that receives the last electron.

• s block: groups 1 and 2, plus helium. Mostly soft, reactive metals, along with hydrogen and helium.
• p block: groups 13 to 18. Holds all the nonmetals except hydrogen and helium, plus the metalloids and some metals.
• d block: groups 3 to 12, the transition metals such as iron, copper, silver and gold.
• f block: the two separate rows at the bottom, the lanthanides and actinides (inner transition elements).

The s and p block elements together are called representative elements. Read more on s and p block elements and d and f block elements. The order in which subshells fill is on the electronic configuration page.

Element types and their colours

Colour on a chemistry periodic table is not decoration. Each colour marks a type of element, and the legend under the chart says which colour is which. Our interactive chart uses ten types, and you can filter by any of them.

Metalloids in the periodic table

A zigzag staircase runs down the p block from boron to polonium. Metals lie to its left and nonmetals to its right. The elements touching the line show mixed behaviour and are called metalloids: boron, silicon, germanium, arsenic, antimony, tellurium and polonium in our data. Silicon is the best known, since it is a semiconductor used in chips and solar cells.

Periodic trends: size, electronegativity and metallic character

Properties change in a regular way as you move along the chart. Three trends come up again and again in exams.

Atomic size

Across a period, from left to right, atoms get smaller. Each step adds one proton, so the nuclear charge rises, but the new electron goes into the same shell. The stronger pull draws the shell inward. Down a group, atoms get bigger, because each period adds a whole new shell further out.

Electronegativity

Electronegativity is how strongly an atom pulls a shared pair of electrons in a bond towards itself. It rises across a period and falls down a group, for the same reasons as size: a small atom with a strong nuclear pull grabs electrons well. Fluorine, at the top right (ignoring noble gases), has the highest value, 3.98. Caesium and francium near the bottom left have the lowest.

Metallic character

Metals tend to lose electrons. That gets easier as atoms get bigger and the outer electron sits further from the nucleus. So metallic character falls across a period and rises down a group. In period 3, sodium is a soft metal, silicon is a metalloid and chlorine is a nonmetal gas.

How many elements are in the periodic table

There are 118 elements in the periodic table today, and all seven periods are full. The total elements in periodic table counts is the same in every current textbook, including NCERT. Of these, about 94 occur in nature (some only in traces) and the rest have been made in laboratories and reactors.

The four newest names fill the end of period 7: nihonium (Nh, 113), moscovium (Mc, 115), tennessine (Ts, 117) and oganesson (Og, 118). IUPAC, the international body for chemical names, approved them after the discoveries were confirmed. Scientists are now trying to make elements 119 and 120, which would start an eighth period.

Counted by type in our data: 40 transition metals, 14 lanthanides, 14 actinides, 11 post-transition metals, 7 metalloids, 7 other nonmetals, 6 halogens, 7 noble gases, 6 alkali metals and 6 alkaline earth metals. Around 90 of the 118 are metals.

Radioactive elements

Radioactive elements have nuclei that are unstable and break down on their own, giving out radiation. In our data 37 elements are marked radioactive.

• Every element from polonium (84) onward is radioactive. Bismuth (83) is the last one treated as stable.
• Two lighter ones break the pattern: technetium (Tc, 43) and promethium (Pm, 61) have no stable isotope at all.
• Well known examples: uranium and plutonium (nuclear fuel), radium (studied by early radiation scientists), radon (a gas that can collect in basements) and thorium.

Elements past uranium (92) are called transuranium elements. None has a stable isotope, which is why their masses appear in square brackets, and the heaviest of them last only seconds or less.

Tricks to remember the first 20 and 30 elements

Most school tests ask for the first 20 elements, and many ask for 30 elements with symbols, mass and valency. Learn them in groups of ten with a silly sentence, where each word starts with the symbol.

Then write them out from memory once a day for a week, filling a blank chart. The elements 1 to 30 page lists the 20 elements of periodic table and the next ten with mass and valency, and a blank grid to fill is on the PDF page.

Periodic table practice problems

Try these without looking, then use the chart above to check.

1. An element has electrons arranged 2, 8, 2. Give its group, period and name.
2. Which is bigger, a sodium atom or a chlorine atom? Why?
3. Name the halogen in period 4.
4. Which block does an element with Z = 29 belong to?
5. Arrange N, O and F in increasing order of electronegativity.

For questions on combining capacity, see valency of elements; for writing formulas of compounds, see chemical formulas and chemistry formulas.

Where the periodic table comes in your syllabus

The topic appears in more than one class, so it pays to learn it properly once.

• Class 9: atomic number, mass number, symbols, and the electron arrangement and valency of the lighter elements.
• Class 10: the chapter on periodic classification of elements in older NCERT books; it covers early attempts, Mendeleev and the modern table.
• Class 11: chapter 3 on periodicity, which explains trends such as atomic radius and the energy needed to remove an electron.
• Class 12 and entrance tests: block-wise chemistry, such as the d and f block chapter, builds directly on the periodic table NCERT layout.

For the history, from triads to octaves to Mendeleev's gaps, read the Mendeleev periodic table story. A list of every name and symbol is on periodic table with names.