These are almost impossible to type on this board so I'll not try. I've never been very successful at it. However, here is what you do.
The atomic numbers (the numbers at the lower left) on the left side of the equation must add up to the same number on the right. The mass numbers (the numbers at the upper left) must add up on left and right side of the equation.
Let's do it all atomic number first.
______ + 2He ==> 2 0n + 98Cf (you must look on the periodic table and see that He is element #2 and Cf is element #98). Now we add them up. Since the unknown is on the left, we add on the right to see what we must have on the left. There is 2*0 + 98 = 98 on the right. So on the left 2 + something must be 98. Obviously the something is 96. So what is element 96 on the periodic table. I believe that is Cm.
Now for the top.
Cm + 4He ==> 2 1n + 244Cf
So on the right we have 2*1 + 244 = 246. On the left we have 4 + something = 246 and the something obviously must be 242. So the full equation looks this way if you let me place the atomic numbers on the left and mass numbers on the right. Check it to see that it all adds up.
96Cm^242 + 2He^4 ==> 2 0n^1 + 98Cf^244.
You see it's as simple as adding the bottom row and the top rows and making each come out the same on both sides of the equation. Let me know if there is something about this you don't understand.
Here we go:
when the following nuclear reaction is completed, the missing element will be:
___+ 4^He ---> 2 v0 1^n+ 244^Cf
Okay, so im given the choices of 242^Cm, 242^Am, 240^Es or 242^Bk....
I already determined that it's not 240 Es (or at least i think I did...) could someone please explain to me what the right answer is? As two of the choices have the same atomic weight and im just not sure how to choose..
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ohh, no I totally get it now. I was just looking at the atomic weight and i didn't even think about the atomic numbers XD thank u so much! this was very helpful!
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