Helium He
Helium is the 2 element in periodic table situated in 1 period.| Symbol | He |
| Number | 2 |
| Atomic weight | 4.0026020 |
| Latin name | Helium |
| English name | Helium |
Electronic configuration of of Helium
He: 1s2
Same electronic configuration has an atom of Helium and H-1, Li+1, Be+2, B+3, C+4, N+5
The order of filling the shells with electrons of Helium (He): 1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p → 6s → 4f → 5d → 6p → 7s → 5f → 6d → 7p.
On the sub level ‘s’ there might be 2 electrons at most, on ‘p’ - up to 6, on ‘d’ - up to 10 and up to 14 on ‘f’
Helium has 2 electrons, let's fill electronic layers in described order:
2 electrons on 1s-sub level
Oxidation state of Helium
Atoms of Helium in compounds have an oxidation state of 0.
The oxidation state is the conditional charge of an atom in a compound: the bond in a molecule between atoms is based on the sharing of electrons, thus, if the atom’s charge virtually increases, then the oxidation state is negative (electrons carry a negative charge), if the charge decreases, then the oxidation state is positive.
Ions of Helium
Valence of He
Atoms of Helium in compounds have valence .
Valence of Helium is an ability of an atom He to build chemical bounds. The valence is based on electronic configuration of atom: electrons participated in chemical bounds are known as valence electrons. In general the valence is:
The number of possible chemical bounds with other atoms
The valence has no sign.
Quantum numbers He
Quantum numbers are defined by the last electron in configuration, for an atom He these numbers are N = 1, L = 0, Ml = 1, Ms = -½
Filling an electronic configuration (gif):
Result:
Ionization energy
The closer the electron is to the center of the atom, the more energy is needed to tear it off. The energy spent on removing an electron from an atom is called ionization energy and is designated Eo. Unless otherwise stated, the ionization energy is the energy of removal of the first electron, and there are also ionization energies for each subsequent electron.
Ionization energy of He:
Eo = 2373 kJ/mol
See all elements of the periodic table
Where is He in the periodic table?
