Write the balanced nuclear equation for the alpha decay of each isotope. 200/84Po
nuclear equation:
thorium-229
nuclear equation:
244/96Cm
nuclear equation:
bismuth-210
nuclear equation:

Explanation:

First, a quick revision of radioactive decay:

During alpha decay, an alpha particle is emitted from the nucleus —- it is the equivalent of a helium atom (i.e. it has a mass of 4 and an atomic number of 2). So, let's take the following question:

Polonium-210 is a radioisotope that decays by alpha-emission. Write a balanced nuclear equation for the alpha decay of polonium-210.

In symbols, the equation becomes

210/84Po--->?+4/2HE

The sums of the superscripts and of the subscripts must be the same on each side of the equation.

Take 4 away from the mass number (210-4 = 206)

Take 2 away from the atomic number (84-2 = 82). Lead is element number 82.

So, the equation is

210/84 Po--->206/82Pb+4/2He

Now let's try one for beta decay — remember that, in beta decay, a neutron turns into a proton and emits an electron from the nucleus (we call this a beta particle)

Write a balanced nuclear equation for the beta decay of cerium-144)

In nuclear equations, we write an electron as 0^-1e.

144/58Ce-->144/59Pr+^0-1e

Here's a fission reaction.

A nucleus of uranium-235 absorbs a neutron and splits in a chain reaction to form lanthanum-145, another product, and three neutrons. What is the other product?

We write a neutron as 1/0n, so the equation is

235/92U +1/0n--->145/57La+X+3 1/0n

Sum of superscripts on left = 236. Sum of superscripts on right = 148. So  X

must have mass number = 236 – 148 = 88.

Sum of subscripts on left = 92. Sum of subscripts on right = 57. So  X

must have atomic number = 92 – 57 = 35. Element 35 is bromine.

The nuclear equation is

235/92U+1/0n--->145/57La+88/35Br+31/0N