How do I solve this ?

Consider the nuclear equation below. 239/94 pu—-> x+ 4/2 he. what is x?

Which element would mostly likely have an electron affinity measuring closest to zero

Two metal blocks that have slightly different temperatures are placed next to one another. after five minutes, they both have lower but equal temperatures. according to the law of conservation of energy, what  most likelyhappened? energy was created inside the blocks.energy was destroyed inside the blocks.energy was absorbed into the blocks from outside the system.energy was transferred from the warmer block to the cooler block.