Which is the answer A, B, or C?

Question

Which isotope, when bombarded with oxygen-18, yields the artificial isotope seaborgium-263 plus 4 neutrons?

A. nobelium-245
B. radium-259
C. californium-245
D. nobilium-249
E. californium-249

I worked out the problem myself, but am unsure if my answer is correct. Could you please show me the results in your steps? (TIA)

Answer 1

I would start by writing a nuclear decay equation. Let x represent your unknown element. It is difficult to format nuclear equations with all the subscripts and superscripts in this text box, so I will go through each part of analyzing the equation separately.

For the masses:

x + 18 = 263 + 4 where x is the mass of your unkwown isotope. I got the numbers from the mass numbers given to you in the problem.

x = 249

This means the mass number of your element must be 249, so that leaves you either D or E. Now we will determine the atomic number of your isotope.

Oxygen's atomic number is 8, Seaborgium's atomic number is 106. A neutron has no atomic number. So...

x + 8 = 106

x = 98

The atomic number of your unknown is 98. #98 on the periodic table is Californium.

Your unknown is Californium-249, answer choice E