Carbon-14 forms nitrogen-14 by
a. alpha decay.
b. beta decay.
c. gamma decay.
d. none of the above

B. Beta decay

Beta decay occurs when a high-speed electron is lost from the atom, converting one of the atom's neutrons into a proton. The mass number of the atom then remains the same but its atomic number is increased by one.

This is the decay taking place because the transition from carbon-14 to nitrogen-14 involves an increase in atomic number by 1.

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

That is a lot of moles that you have