Question

consider the phosphorus tetrachloryl (pcl₄⁺) cation.
what is the central atom? enter its chemical symbol.
how many lone pairs are around the central atom?
what is the ideal angle between the phosphorus - chlorine bonds?
compared to the ideal angle, you would expect the actual angle between the phosphorus - chlorine bonds to be ...

Explanation:

Step1: Identify central atom

In $PCl_{4}^{+}$, the central atom is the one with the least - electronegative element among the bonded atoms. Phosphorus (P) is less electronegative than chlorine (Cl), so the central atom is P.

Step2: Determine lone - pairs

Phosphorus has 5 valence electrons. In $PCl_{4}^{+}$, it forms 4 single bonds with 4 chlorine atoms. The number of valence electrons used in bonding is 4. The charge of the ion is + 1, which means one electron is lost. So the number of non - bonding electrons (lone pairs) is $\frac{5 - 4-1}{2}=0$.

Step3: Find ideal bond angle

The electron - pair geometry of $PCl_{4}^{+}$ is tetrahedral (since there are 4 bonding pairs and 0 lone pairs around the central atom). The ideal bond angle in a tetrahedral geometry is $109.5^{\circ}$.

Step4: Compare ideal and actual bond angles

Since there are no lone pairs around the central atom in $PCl_{4}^{+}$, there is no lone - pair repulsion. So the actual bond angle is equal to the ideal bond angle.

Answer:

1. P
2. 0
3. $109.5$
4. the same