Answer : For a species to be diamagnetic it needs to have no unpaired electrons and for paramagnetic the species needs t have unpaired electrons.
Answer 1) :
Electronic configuration of carbon is
So, electronic configuration of will be
, as it has given its two electrons present in the outermost valence shell.
This molecule of will behave as diamagnetic species as there are no unpaired electrons in the orbital.
Answer 2)
Explanation : The electronic configuration of Lithium is
When lithium is in state it will have electronic configuration as
This shows that Lithium has one electron which is available in 2p orbital, and it is also unpaired.
Therefore, the species will behave like a paramagnetic substance.
Answer 3)
Boron has electronic configuration as ,
So, the excited state of will be
,
Here, Boron in excited state has one unpaired electron in 2p orbital rest 2 electrons are paired in the 2p orbital.
This will make as a paramagnetic substance.