Period 1 element

The first period of the periodic table of the elements contains all the chemical elements that have only one electron shell in the atom. This is also called the valence shell electron shell of the atom. As this first electron shell can accommodate a maximum of two electrons, there are only two chemical elements in the first period. The valence shell, which largely determines the properties of a chemical element, is ready fully occupied with elements of the 1st period with 2 electrons. For all other periods, the valence shell is fully occupied until 8 electrons.

Excerpt from the Periodic Table

Common Features

Both the chemical elements of the first period are gaseous under standard conditions, are colorless gases and have diamagnetic properties.

Helium in a discharge tube

Magic Number

The chemical element with the atomic number of helium has two in the ground state of the nucleus is more stable than neighboring nuclides. This particular order number is called the magic number.

Number of electrons in the electron shells

List

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8

  • Group of the periodic table
  • Period - 1 element
Group (periodic table) Atomic nucleus Period (periodic table) Period 2 element Period 3 element Period 4 element Period 6 element Period 7 element Period 8 element
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