Interactive Periodic Table of Elements
A periodic table explorer: search any element by name, symbol or atomic number for its atomic weight, group, period and electron configuration.
Reactive nonmetal
14 / 2
p-block
Solid
[He] 2s2 2p2
2, 4
2.55 (Pauling)
1086.5 kJ/mol
Not known
Not known
1.821 g/cm³
Ancient Egypt
All 118 confirmed elements. Atomic masses are the IUPAC standard atomic weights — for elements with no stable isotope, the value is the mass number of the most stable known isotope, which is why it is shown as a whole number. Blank fields are genuine gaps in the measured data rather than zeroes.
What Interactive Periodic Table of Elements Does
The periodic table is ordered by atomic number (the number of protons in the nucleus) and arranged so that elements with similar chemistry fall into the same column. That arrangement was worked out before anyone knew what an electron was, and it holds up because a column shares the same outer-shell electron count, which is what determines how an element reacts.
All 118 confirmed elements are here, with atomic mass, electron configuration, phase, melting and boiling points, density, electronegativity and first ionization energy. Masses are the IUPAC standard atomic weights, which are averages across the isotopes found in nature. That is why chlorine is 35.45 rather than a whole number, and why it is a range rather than a constant for some elements.
For elements with no stable isotope, there is no natural mixture to average, so the convention is to quote the mass number of the most stable known isotope. That is why the bottom of the table reads in whole numbers.
The last stretch of the table is largely predicted rather than measured. Elements past about 104 have been made a few atoms at a time with half-lives in milliseconds, so most of their properties come from extrapolating periodic trends. Where a value is genuinely unknown, this says so rather than showing a zero.
How to Use Interactive Periodic Table of Elements
- Type an element name or symbol in the search input
- Click any element box in the grid to spotlight its properties
- Review atomic mass, orbital electron configuration, and chemical family
Formula Used by Interactive Periodic Table of Elements
How the table is organized
period = the outermost occupied shell · group = the outer-shell electron count · block = the subshell being filled (s, p, d, f)
- atomic number Z
- protons in the nucleus, which define the element and the ordering
- standard atomic weight
- the isotope-abundance-weighted average mass, in unified atomic mass units
- electron configuration
- written from the previous noble gas, so iron is [Ar] 3d⁶ 4s²
Worked example
Chlorine, atomic number 17.
- Period 3, group 17 — seven outer electrons, one short of a full shell
- Configuration [Ne] 3s² 3p⁵
- Mass 35.45, because natural chlorine is roughly 76% chlorine-35 and 24% chlorine-37
Result: One electron short of stability, which is why the halogens are so reactive and why chlorine forms a −1 ion.
The categories, and what they share
| Category | Where | Behavior |
|---|---|---|
| Alkali metals | Group 1 | One outer electron, given up eagerly — soft, and violently reactive with water |
| Alkaline earth metals | Group 2 | Two outer electrons; reactive, though less so |
| Transition metals | Groups 3–12 | Filling a d subshell; multiple oxidation states, colored compounds |
| Post-transition metals | Right of the transition block | Softer, lower melting points than transition metals |
| Metalloids | The staircase | Intermediate — the basis of semiconductors |
| Reactive nonmetals | Upper right | Gain or share electrons; the elements of organic chemistry |
| Halogens | Group 17 | One electron short of a full shell, so highly reactive |
| Noble gases | Group 18 | Full outer shell, so almost entirely unreactive |
| Lanthanides | Row below, 57–71 | Filling 4f; chemically very similar to each other |
| Actinides | Row below, 89–103 | Filling 5f; all radioactive |
Trends worth knowing
These are why the shape of the table is useful rather than decorative.
| Property | Across a period | Down a group |
|---|---|---|
| Atomic radius | Decreases — more protons pull the same shell in | Increases — another shell is added |
| Ionization energy | Increases | Decreases |
| Electronegativity | Increases | Decreases |
| Metallic character | Decreases | Increases |
How to Read Your Result
The column tells you the chemistry
Elements in a group share their outer-shell electron count, which is what reacts. Sodium and potassium behave alike because both have one outer electron to lose; fluorine and chlorine behave alike because both are one short of a full shell.
Atomic mass is an average, not a count
Standard atomic weights average over the isotopes found on Earth, weighted by abundance. That is why they are rarely whole numbers, and why IUPAC now publishes intervals rather than single values for a dozen elements whose isotopic composition varies measurably by source.
Missing values are honest gaps
Several superheavy elements have been produced only in single-atom quantities with half-lives too short to measure a melting point. Where a property has never been measured, it is shown as unknown rather than filled in with a prediction.
The f-block is drawn below to save width
The lanthanides and actinides belong between groups 3 and 4. Inserting them inline would make the table 32 columns wide, so convention pulls them out; they are part of periods 6 and 7 rather than a separate appendix.
Limitations & Accuracy Notes
- Atomic weights are the abridged IUPAC standard values. For elements whose isotopic composition varies by source, IUPAC publishes an interval and this shows a representative value.
- Melting points, boiling points and densities are measured at standard pressure and vary with allotrope: carbon as graphite and as diamond differ substantially.
- Electronegativity is on the Pauling scale, which is not defined for the noble gases and several synthetic elements.
- Properties for elements above roughly 104 are largely predicted rather than measured.
- Isotopes, half-lives and decay chains are outside the scope of this table.
Frequently Asked Questions
What information is provided for each chemical element?
Each element card displays the atomic number, chemical symbol, standard atomic weight, chemical classification category, periodic table period/group, and electron configuration.
How do I search for a specific element?
Type any element name (e.g. Gold), atomic symbol (e.g. Fe), or atomic number (e.g. 79) into the instant search box.
Why are some elements grouped into blocks (s, p, d, f)?
The block reflects which electron subshell an element’s outermost electrons occupy, which largely determines its chemical behavior; elements in the same block tend to share similar reactivity patterns.
Are all 118 elements naturally occurring?
No. Elements beyond atomic number 94 (plutonium) are essentially all synthetic, created in laboratories or nuclear reactors rather than found in nature in measurable quantities.
How many elements are there?
118 are confirmed and named, running from hydrogen to oganesson. Everything beyond uranium at number 92 is synthetic, and the heaviest have been produced only in tiny quantities with half-lives measured in milliseconds.
Why is atomic mass not a whole number?
Because it is a weighted average across the naturally occurring isotopes of that element. Chlorine sits near 35.45 because it is a mixture of chlorine-35 and chlorine-37 in roughly a three-to-one ratio, not because any single atom has that mass.
What does the group and period tell me?
The period is the row and corresponds to the outermost occupied electron shell. The group is the column and elements within one share an outer electron configuration, which is why they behave similarly. The whole table is organized around that.
What is an electron configuration notation?
A shorthand for which orbitals the electrons occupy, such as 1s2 2s2 2p6. It explains chemical behavior better than any other single property, because bonding is almost entirely about the outermost electrons.
Can I cite this for coursework?
The page states the source of its atomic data. For formal work, cite that primary source rather than this page.
Is anything sent to a server?
No. The element data is bundled with the page.
References & Further Reading
- IUPAC — standard atomic weights — The authority for the atomic masses shown, which were spot-checked against the 2021 abridged values
- Periodic-Table-JSON — The public-domain dataset this table is generated from