Regarding Prompt neutrons

Thermal neutrons are

Atoms may be regarded as comprising protons, neutrons and electrons. If the mass of a neutron were halved and that of electron was doubled , the atomic mass of ""_(6)C^(12) would :

The reaction which disintegrates neutron is or neutron is emitted (which completes first):

The reaction which disintegrates neutron is or neutron is emitted (which completes first):

The charge on a neutron is

How was the neutrons discovered ? Mention the characteristics of neutrons.