Question

How many valence electrons does lithium have?

Answer 1

Hint: The answer to this question is dependent on the fact that the valence electrons are the electrons that are present in the outermost orbit of the atom and it can be found by writing the electronic configuration of the atom.

Complete answer:
In the lower classes, we have studied about the basic topic of general chemistry which tells us about the structure and composition of an atom and also about the periodic table and how the atoms are arranged in it.
Let us now see the electronic configuration of the beryllium atom according to the atomic number.
- Atoms are composed of nuclei in which the neutrons and protons are concentrated in it and the negatively charged particles called the electrons revolve around the orbit of the nucleus of an atom.
- The number of protons in an atom is nothing but its atomic number and also the total number of protons are always equal to the total number of electrons in an atom.
Based on these facts, we can write the electronic configuration of an atom. Now, let us write the electronic configuration of lithium atom which has the atomic number 3 with the atomic symbol $Li$ and the configuration is $1s^{2}2s^1$.
- Here, the outermost shell is 2s and the total number of electrons present in this shell is 1.
Therefore, the correct answer is that Lithium has 1 valence electron.

Note:
Note that the valence electrons are also called as the electrons in the last ring or the outermost orbit of the atom. This term is not to be confused with valency of an atom as valency is the measure of the combining capacity of the atom with the other atom/s when it forms a molecule.