Make the electronic and graphic formulas of the atom of the element with atomic number 12 what is its valence?

The atomic number 12 in the periodic table of Mendeleev has a magnesium atom – Mg.

The electronic formula for magnesium (Mg) is: 1s 2 2s 2 2p 6 3s 2, where the numbers 1,2,3 denote the levels of the arrangement of electrons, and the letters s, p denote the sublevels of the arrangement of electrons, and the numbers and, which are located in the “degree »The number of electrodes is indicated directly. It is worth knowing that only two electrons can be located on one sublevel and they are located with opposite spins. The sequence of filling the electronic levels is carried out according to a strict sequence: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p.

The physical meaning of the serial number is the number of electrons in an atom, for magnesium it is 12.

The physical meaning of the period number is the number of electronic arbitals or levels, for magnesium it is 3.

The physical meaning of the group number is the number of valence electrons, the number of electrons at the last energy level for the elements of the main subgroup, for magnesium it is 2, thus the valence of magnesium is two.