Can you write the nuclear decay equation for the beta decay of iodine-131?

1 Answer
Aug 20, 2014

Answer:

The equation is #""_53^131"I" → ""_54^131"Xe" + color(white)(l)_text(-1)^0"e"#

Explanation:

β decay is a process in which a nucleus emits an electron.

The nuclear symbol for a β particle is #color(white)(l)_text(-1)^0"e"#.

In any nuclear equation, the sum of the subscripts (atomic numbers, #"Z"#) and the sum of the superscripts (atomic masses, #"M"#) must be equal on each side of the equation.

For the β decay of iodine 131, we have

#""_53^131"I" → color(white)(l)_text(Z)^"M""X" + color(white)(l)_text(-1)^0"e"#

Hence

#131 = "M" + 0#, so #"M" = 131#
#53 = "Z - 1"#, so #"Z" = 53 + 1 = 54#

The element #"X"# with #"Z = 54"# is #"Xe"#.

So the equation is

#""_53^131"I" → ""_54^131"Xe" + color(white)(l)_text(-1)^0"e"#

Note that in β decay, the product has the same mass number but an atomic number that has increased by 1.

Here's a video on writing β decay equations.