Chapter 15, Problem 9RAT

To determine

The correct option for the statement “How many electrons are there in the third shell of sodium, Na (atomic number 11)?”.

Answer to Problem 9RAT

The correct option for the statement “How many electrons are there in the third shell of sodium, Na (atomic number 11)?” is option (b).

Explanation of Solution

Sodium atom is present in first group of the periodic table. The atomic number of sodium atom is 11 and its atomic mass is $23\text{ u}$. the number of protons present in its nucleus is $11$and the number of electron is same as a proton is equal to $11$.

Electron distribution in sodium atom, according to octal rule, is $2,8,1$. There are $2$electrons present in its first shell, $8$electrons in its second shell and $1$ electron in its third valence shell. Thus, there is one electron present in the third shell of the atom.

Conclusion:

Therefore, The correct option for the statement “How many electrons are there in the third shell of sodium, Na (atomic number 11)?” is option (b).