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Pookiieluvzyhu
18. What particle will balance the following nuclear equation?
1. alpha emission of Po-209 209 . . . . . . .4 . . Po .==>. . He .+ . . .? .84 . . . . . . .2 Ignore the dots, I just use them for spacing. Po has 209 on top (atomic mass) and 84 on bottom (atomic number). An alpha particle is He-4 (atomic mass = 4, atomic no. He = 2). So what is the missing species? Look at the numbers on top. We have 209 on the left side of the arrow. So we need a total of 209 on the right side of the arrow. So far we have 4 (from He). 209 - 4 = 205. So 205 goes on top of the missing species. Now look at the bottom numbers. We have 84 on the left of the arrow. The sum of the bottom numbers on the right side of the arrow must also be 84. So far we have 2 (from He). 84 - 2 = 82. What is element 82? Pb, lead. So the missing species is Pb-205. 209 . . . . . . . . .4 . . . . . . 205 . . Po . .==> . . .He . .+ . . . .Pb .84 . . . . . . . . ..2 . . . . . . . 82 2. Decay of Ca-45 to Sc-45 45 . . . . . . . . .45 . .Ca . .==> . . .Sc . . .+ . . .? 20 . . . . . . . . .21 Again, the numbers (top and bottom) on one side must equal those on the other side. On top, we have 45 on the left and 45 on the right. So the missing species has 0 on top. On bottom, we have 20 on the left and 21 on the right. The missing species must be -1 on bottom. What species has 0 on top and -1 on bottom? That's an electron, or a beta particle. 45 . . . . . . . . .45 . . . . . . .0 . .Ca . .==> . . .Sc . . .+ . . e 20 . . . . . . . . .21 . . . . . ..-1
This is Beta decay and will emit an e ^-