`BF_(3)` and `B(OH)_(3)` are isoelectronic, but the former is a gas, whereas the later is a solid because

Why oxygen is a gas, whereas sulphur is a solid?

Oxygen is gas but sulphur is solid because

is it true that CO2 is a gas whereas SiO2 is a solid.

N_(2), CO, CN^(-) and NO^(+) are isoelectronic but the former is chemically inert and later three are very reactive, why?

NH_(3) and BF_(3) form adduct readily because they form :

Give reasons for the following: CO_2 is a gas whereas SiO_2 is a solid.

NH_(3) and BF_(3) from adduct readily because they from

NH_(3)and BF_(3) from adduct readily because they from