Question

What is the number of valence electrons in tin?

Answer 1

Hint :As we know that valence electrons are the electrons that are present in the outermost shell of an atom. If we have to find the valence electrons, then we must have to know the atomic number of that atom. We can use atomic numbers to write the electronic configuration and then find the electrons in the valence shell.

Complete Step By Step Answer:
We should understand the meaning of the term valence. It is basically the electrons in the valence shell of an atom called valence electrons. To understand this concept let us consider an example of tin. As we know that the atomic number of lithium is three, and it has two electrons in the first shell and one electron in the second shell, that is basically a valence shell.
Tin is located in the group $14$ of the periodic table, which means that it has four electrons in its outermost shell, i.e. four valence electrons. Tin has an atomic number of $50$ , so right from the start you know that its electron configuration must account for a total of $50$ electrons. We will have;
So, we can see that its electronic configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^2$ also, we can say that there is one electron in the valence shell. The fifth energy level, $n=5$ , is tin's outermost energy shell. As you can see, tin has a total of four electrons on this level.
Therefore, two electrons in the $5s$ subshell and t electrons in the $5p$ subshell. Once again, we can conclude that tin has four valence electrons.

Note :
Remember that as we know that valency is the combining power of an element. It is found that elements in the same group have the same valence in the periodic table. Basically the valence of an element is related to the electrons that are present in the outer shell.