Question

How many electrons are present in the valence shells of the central atoms in the molecules of \(\mathrm{BeCl}_{2}, \mathrm{BF}_{3}\) and \(\mathrm{PCl}_{5}\) ?

Short answer

Answer: The number of electrons present in the valence shells of the central atoms in BeCl2, BF3, and PCl5 are 2, 3, and 5 electrons, respectively.

Step-by-step solution

Finding the Group Number of the Central Atom

Identify the group number of the central atoms in the periodic table. Be is in Group 2, B is in Group 13, and P is in Group 15.

Calculating Valence Electrons for Be in BeCl2

Since Be (beryllium) is in Group 2, it has 2 valence electrons. So, the central atom Be in the BeCl2 molecule has 2 electrons in its valence shell.

Calculating Valence Electrons for B in BF3

B (boron) is in Group 13. It has 3 valence electrons. So, the central atom B in the BF3 molecule has 3 electrons in its valence shell.

Calculating Valence Electrons for P in PCl5

P (phosphorus) is in Group 15, so it has 5 valence electrons. Therefore, the central atom P in the PCl5 molecule has 5 electrons in its valence shell.

Summing Up the Results

In summary, the number of electrons present in the valence shells of the central atoms in BeCl2, BF3 and PCl5 are: - BeCl2: 2 electrons - BF3: 3 electrons - PCl5: 5 electrons.