I believe the answer is Zinc because it has 30protona
A negativley charged ion is the answer
The traditional calcium atom has twenty protons and twenty electrons making it neutral.
The calcium in the pic is a calcium ion so the number of protons and electrons are not equivalent.
Since it's 2+ that means the ion is positively charged and for that to happen electrons are away.
So 20-2=18
There are 18 electrons
It is a binary direct bandgap semiconductor commonly used in light-emitting diodes since the 1990s
