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Period 1 element
Introduction
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. | ||||||||||||||||||
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