Electronic Configuration in Periods

Electronic configuration of the elements in periods can be found by using following points:

• The period of the element is the value of n, the primary quantum number, for the valence shell.

• The number of electrons that can be accommodated by different energy levels varies.

• The maximum number of electrons that can be accommodated in an energy shell is given by 2n², where n is the energy level. It is the greatest number of electrons that a given energy level can allow. So the first energy level (K shell) can hold up to 2 electrons, the second (L shell) up to 8 electrons, the third (M shell) up to 18 electrons, and so on.

• The second period begins with Lithium and Beryllium, both of which have three and four electrons, respectively, and so the final electrons reach level two.

• The third period begins with Sodium and finishes with Argon, filling the 3s and 3p orbitals in that order. There are eight elements in this period as well.

• The level 4s are filled first in the fourth period with n = 4. It all starts with potassium. However, we know that the 3d orbital must be full before the 4p orbital can be filled. Scandium is the first of the 3d transition elements. The 3d orbital gets completely filled with electrons in the case of zinc.

• The level 5s are filled first in the fifth period with n = 5. The 4d transition series, which begins with the Yttrium, dominates this time. The 5p orbital is completely filled by Xenon at the end of the period.

• With n = 6, the sixth period has 32 elements, with electrons filling the 6s, 4f, 5d, and 6p orbitals. Cerium signifies the entry of electrons into the 4f orbital, resulting in the lanthanide series of 4f-inner transition elements.

• The radioactive elements with electrons filling the 7s, 5f, 6d, and 7p orbitals belong to the seventh period with n = 7. Similar to period 6, this period causes electrons to fill the 5f orbital, giving rise to the actinide series of 5f-inner transition elements.

Electronic Configuration is the arrangement of electrons in orbitals around an atomic nucleus. Electronic Configuration of a molecule refers to the distribution of electrons in various molecular orbitals. The number of electrons in bonding and antibonding molecular orbitals of a molecule or molecular ion can be calculated from its electronic configuration.

In this article, we will learn about Electronic Configuration, Electronic Configuration in Periods, and Electronic Configuration in Groups.