Which of the following crystals would be most brittle and hard?

ag

zns

f2

c12h22o11

ZnS, more ionic character than any of the others 
Ar is a gas 
I2 sublimates readily at room temperature 
sucrose = covalent, hard crystals and brittle but covalent

There is one s orbital, and there are three p orbitals, five d orbitals, and seven f orbitals. thus, the answer is b. do not confuse the number of orbitals in a subshell with the number of electrons the subshell can hold. each orbital can hold two electrons, so the capacity of an nf subshell is 14 electrons.

Copper, silver, aluminum, cobalt, chromium, mercury