Subtract the number of protons from the mass number.
<span>the element that requires the least amount of energy to remove the outer-most electron from a gaseous atom in the ground state is s</span><span>odium</span>
The answer should be C
The reason for this is because:
There are 2 "I" on the right side of the equation but only 1 on the left. This means you need to add a 2 on the "KI" to get two "I".
But now there are 2 "K" on the left side and only 1 on the right, meaning you need to add a 2 to the "KCL". This makes it balanced
It’s the second one if you need more help tell me
