Question

How many valence electrons does the last element of a period contain?

Answer 1

Solution:

Valence electron:

The outermost shell is referred to as the valence shell, and the electrons located within it are referred to as valence electrons.

Periods:

The horizontal rows of the periodic table are called periods.

According to the question:

• The periodic table has periods and groups in which elements are arranged in accordance with their atomic number.
• The last element of a period means the last group of elements of the periodic table.
• They are the noble gas elements having the last shell filled by $8$ electrons except helium.
• Example: The atomic number of Neon($\mathrm{Ne}$) is 10 and the configuration is 2,8. so the last outermost valence electron is 8
• Helium$\left(\mathrm{He}\right)$is the only inert gas having 2 valence electrons.

Thus, the last element of the period contain $8$ valence electrons.