Periodic Table

All 118 elements with atomic mass, electron configuration and group; search, filter and compare.

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C

Carbon

Element 6 · Reactive nonmetal

Properties of Carbon
Atomic number	66 protons in the nucleus
Atomic mass	12.011 g/molStandard atomic weight (IUPAC)
Category	Reactive nonmetal
Group	14
Period	2
Block	p-block
Electron configuration	[He] 2s² 2p²
Electronegativity	2.55Pauling scale
State at room temperature	Solid

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Second element

Sodium and Chlorine side by side
Property	Na Sodium	Cl Chlorine	Difference
Atomic number	11	17	6
Atomic mass	22.990	35.45	12.46
Category	Alkali metal	Reactive nonmetal
Group	1	17
Period	3	3
Block	s	p
Configuration	[Ne] 3s¹	[Ne] 3s² 3p⁵
Electronegativity	0.93	3.16	2.23
State	Solid	Gas

Electronegativity difference 2.23. Large difference, so a bond between them would be mostly ionic. This is a rule of thumb, not a firm line.

About this table

Rows are periods: the number of electron shells. Columns are groups: elements in a group have the same number of outer electrons, so they behave alike. The block (s, p, d or f) is the kind of subshell being filled.

Atomic masses are IUPAC standard atomic weights, abridged. A number in brackets, like [98] for technetium, means the element has no stable isotopes; it is the mass number of its longest-lived isotope. Electronegativity is on the Pauling scale. Configurations for elements 104 to 118 are predictions.

Lanthanum to lutetium and actinium to lawrencium sit in the two rows below the main table, as in most school books; they have no group number.

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