Assertion: $H_2O$ and $XeF_4$ both have a plane of symmetry.
Reason: $H_2O$ is a polar molecule,whereas $XeF_4$ is a non-polar molecule.

Which of the following species among $BF_3, SnCl_2, SnCl_4$ act as Lewis acids?

Which of the following odd electron species is planar?

Number of electron-deficient molecules among the following $PH_{3}$,$B_{2}H_{6}$,$CCl_{4}$,$NH_{3}$,$LiH$,and $BCl_{3}$ is ..... .

Fill in the blanks given below:
$(i)$ The attractive force which holds atoms,molecules,and ions together is called ......... .
$(ii)$ First of all,............ and ............ scientists provided detailed information about valency.
$(iii)$ In the structure of an atom,when only the electrons of the outermost shell participate,they are known as ............ .
$(iv)$ The symbol used to represent valence electrons in an atom is called ........ .

In solid state,$PCl_5$ is a/an