1.Cyclopropene 2 electrons (n = 0); the delocalization is inturrupted due to sp3 methylene; Nonaromatic

2.Cyclopentadiene

4 electron system( even number of pairs); Does not have an uninterrupted ring of p orbital bearing atoms (conjugation); Nonaromatic. 4 electron (even number of pairs; 4n, n = 1;Cyclic, planar, uninterrupted ring of p orbital bearing atoms (conjugation); antiaromatic 6 electron system (4n+2, n = 1), cyclic, planar with conjugation; Aromatic Cyclopentadiene Cyclopentadienyl cationCyclopentadienyl anion

Reason :

The pKa of cyclopentadiene is 15, which is extraordinary for hydrogen bonded to a sp3 carbon. The reason for this low pKa is its high tendency to become aromatic by releasing a proton.