alpha emissions and neutrons?

Question

A nuclide of Sg-263(Z=106) was made, together with four neutrons, by bombarding an isotope of Cf with O-18. The nuclide of Sg then decayed by three alpha emissions. What is the composition of Cf and what is the element after the decay of Sg?

Answer 1

Hmmm, Cf has Z=98, and A=?

Cf(98,?) + O(8,18) ===> Sg(106,263) + 4 n°

So you know the total atomic mass of the Cf + O = Sg + n°, thus:

Cf = Sg + n° - O = 263 + 4 - 18 = 269

So your initial Cf must have A = 269
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Now, the Sg decays by three alpha (α) emissions:

Sg (106,263) - 3 α ==> ?

Each α = two protons + two neutrons, so:

Sg(106,263) - 6 protons - 6 n° = XX(100,257)

The element with Z = 100 is Fermium (Fm), so what you end up with is Fermium-257