What are compounds?

a. pure substances

b. heterogeneous mixture

c. homogeneous mixture

I think the correct answer is option A. Pure substances can be considered as compounds. Compounds are molecules made of atoms from different elements held together by chemical bonds. Pure substances are these compounds that exist alone no other substance.

The answer options is d

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.