it would need to gain 2 more for it to achieve a stable configuration
the best way to remember this is the noble gasses all have 8 valence electrons and that they are the most stable elements on the periodic table
The number of hours required : 37.2 hours
<h3>Further explanation</h3>
Given
⁴²K (potassium -42)
Required
The number of hours
Solution
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
Based on Table N(attached), the half-life for ⁴²K is 12.4 hours, which means half of a sample of ⁴²K will decay in 12.4 hours
For three half-life periods :

Yes, you're right the answer is 0,02 moles.
An not sure,, but maybe 24. don't take my word for it
An example of an atom that has no charge is one that has a. 2 protons, 2 electrons, and 1 neutron.
To be neutral an atom must have the <em>same number</em> of protons (+) and electrons (-).
Only then will the <em>charges cancel</em> and give a neutral atom.