Question 59da9

Oct 8, 2017

Here's what I got.

Explanation:

The incomplete nuclear equation given to you

""_ 19^42"K" -> ""_ (-1)^(color(white)(-)0)"e" + ?#

describes the beta decay of potassium-42. You can tell that this is the case because the radioactive nuclide emits an electron, also known as a beta particle.

In beta decay, a neutron located inside the nucleus is converted to a proton. When this happens, the nuclide emits a beta particle and an electron antineutrino, ${\overline{\nu}}_{3}$.

As a result of the beta decay, the atomic number of the nuclide increases by $1$ and the mass number of the nuclide remains unchanged.

This means that the balanced nuclear equation that describes the beta decay of potassium-42 looks like this

$\text{_ 19^42"K" -> ""_ 20^42"Ca" + ""_ (-1)^(color(white)(-)0)"e} + {\overline{\nu}}_{e}$

Notice that you have

• $42 = 42 + 0 \to$ conservation of mass
• $19 = 20 + \left(- 1\right) \to$ conservation of charge