Question

Briefly explain why sulfur and phosphorus can form complicated molecules, but nonmetals in period 2 tend to form only diatomic molecules

Answer 1

see below

Step-by-step explanation:

Sulfur and phosphorous can violate the octet rule and have an expanded octet, so molecules of these elements can contain more than eight valence electrons. In contrast, nonmetal elements in period 2 can't have an expanded octet because they don't have d orbitals. These elements must obey the octet rule and can hold only up to eight valence electrons. Period 2 elements can fill their outer orbitals by covalently bonding with one other atom of the same element.