Question

How many valence electrons are in sodium ions?

Answer 1

As we know that the valence electrons are those electrons which are present in the outermost shell of an atom. And if the valence shell is not fully filled or half-filled which are the most stable conditions for an atom, then atoms can lose or gain electrons to reach their stable configuration state.

Complete step-by-step answer:
As we know that valence shell electrons are those which are present in the outermost shell of an atom. Now, we know that the atoms that have the capacity to lose an electron to attain the stable noble gas configuration then acquire a positive charge on them and when any atom gains an electron to attain the stable noble gas configuration, then they acquire a negative charge on them and become ions.
We also know that the positively charged ions are commonly called cations and negatively charged ions are generally known as anions.

Now talking about sodium, we know that sodium possess an atomic number of $11$ and the electronic configuration of sodium is shown as $1{s^2}2{s^2}2{p^6}3{s^1}$ therefore, having $11$ electrons. As we can see that the sodium has one electron in its valence shell. And thus, it can lose this electron to become stable so as to become an ion. And now the configuration becomes $1{s^2}2{s^2}2{p^6}$ and the electron becomes $10$ thereby becoming stable. Therefore, there are $10$ valence electrons in sodium ions.

Note: Always remember that sodium represents $Na$ and after losing one electron sodium becomes $N{a^ + }$. It has now attained the same energy level as noble gases like neon and two atoms or ions which possess the same number of electrons are termed as isoelectronic species.