when metals form ions they tend to form
When metals form ions, they tend to do so by losing their electrons  to gain a positive charge. Losing negatively charged electrons  causes the metals to become more positiv â¦ e due to having more  protons.
As you may notice, they can form ions by either losing or gaining electron in 4s orbital. In the chemistry of the transition elements, the 4s orbital behaves as the outermost, highest energy orbital. When these metals form ions, the 4s electrons are always lost first, leading to a positive charge on ion. Gaining any electron in 4s orbital would decrease the stability of anion thus formed. So, they form only cations (positive ions) .