1. What type of reaction is this?

244 Pu+He+242U

Its a Nuclear reaction

Explanation:

A nuclear reaction is a type of reaction that involves the nucleus of an atom and does not affect the electrons like chemical reactions. The the reaction is known as a nuclear reaction;

²⁴⁴Pu + ⁴He → ²⁴⁰U

The above type of nuclear reaction is an alpha decay in which a radioisotope Pu-244 undergoes alpha decay to form U-240. An Alpha particle is equivalent to the nucleus of a helium atom (⁴₂He). Therefore, when a radioisotope undergoes alpha decay the mass number decreases by 4 and the atomic number decreases by 2.