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A period 1 element is one of the chemical elements in the first row (or period) of the periodic table of the elements.
Period one is much shorter than any other row in the table, and contains only two elements, hydrogen and helium. In a quantum mechanical description of atomic structure, this period corresponds to the filling of the 1s orbital. Period 1 elements do not obey the "octet rule".
These are:
| Group | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| # Name | 1 H | 2 He | ||||||||||||||||
| e--conf. | ||||||||||||||||||
Element categories in the periodic table
| Metals | Metalloids | Nonmetals | |||||||
| Alkali metals | Alkaline earth metals | Inner transition elements | Transition elements | Other metals | Other nonmetals | Halogens | Noble gases | ||
| Lanthanides | Actinides | ||||||||
| Periodic tables | |
|---|---|
| Layouts | Standard · Vertical · Full names · Names and atomic masses · Text for last · Huge table · Metals and nonmetals · Blocks · Valences · Inline f-block · 218 elements · Electron configurations · Atomic masses · Electronegativities · Alternatives |
| Lists of elements | Name · Atomic symbol · Atomic number · Boiling point · Melting point · Density · Atomic mass |
| Groups | 1 · 2 · 3 · 4 · 5 · 6 · 7 · 8 · 9 · 10 · 11 · 12 · 13 · 14 · 15 · 16 · 17 · 18 |
| Periods: | 1 · 2 · 3 · 4 · 5 · 6 · 7 · 8 |
| Element categories | Alkalis · Alkaline earths · Lanthanides · Actinides · Transition metals · Metals · Metalloids · Nonmetals · Halogens · Noble gases |
| Blocks | s-block · p-block · d-block · f-block · g-block |
This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia
