1 1

Hydrogen, H, element 1

Nonmetal· Period 1· Group 1· s-block

Configuration 1s1

Atomic weight
1.008Da
Phase
gas
Density
8.2×10−5g/cm³
Melting point
13.99K -259.16 °C
Boiling point
20.271K -252.88 °C
Electronegativity
2.2

Colourless, odourless gaseous chemical element. Lightest and most abundant element in the universe. Present in water and in all organic compounds. Chemically reacts with most elements. Discovered by Henry Cavendish in 1776. Description from mendeleev.

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The outermost shell: the valence electronsThe inner shellsThe nucleus One bead for each electron, on the ring of its shell, counted from the nucleus out. The rings turn at their own pace; the model is Bohr's picture of the atom, which places electrons in shells but not on true orbits.

Atomic properties

4 of 5 fields have a value for hydrogen

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
1.008Da
Source: mendeleev
Electron configuration
1s1
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s1
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
1
Source: Worked outfrom electron configuration

No data uncertainty of the atomic weight.

Screening of each subshell

Clementi's screening constants: how much of the nucleus's charge the other electrons hide from an electron in each subshell. What is left is the effective nuclear charge it feels.

SubshellScreening σEffective charge Z − σ
1s01