Question

how to metal atoms form ions?
they gain protons
they gain electrons
they drop protons
they drop electrons

Explanation:

Metal atoms have relatively few electrons in their out - most energy levels. To achieve a stable electron configuration (usually a full outer shell), they tend to lose (drop) electrons. Losing electrons results in the formation of positively charged ions (cations). Protons are in the nucleus and are not involved in ion - formation in this context. Gaining electrons is characteristic of non - metals to form anions.

Answer:

They drop electrons