Question

An element 'P' has atomic number 56. What will be the formula of its halide?

• A. PX
• B. $P{X}_2$
• C. $P{X}_3$
• D. $P_2{X}_2$

Answer 1

The correct option is B $P{X}_2$

Element 'P' with atomic number 56 will lose two electrons to form $P^{2+}$ ion with 54 electrons corresponding to the stable noble gas electronic configuration.

Halogen gains one electron to form $X^{-}$ ion. One $P^{2+}$ ion combines with two $X^{-}$ ions to form $P{X}_2$.

Note: In a neutral molecule, the total charge on cations is numerically equal to the total charge on anions.