when metals react they (gain/lose) electrons. as you go down any group containing metals, it becomes easier to lose electrons because they are further away from the attractive force of the positive nucleus.

When metals react they lose electrons.

Explanation:

An ion is defined as a molecule or atom made up of a different number of electrons and protons. This makes the electric charge of the molecule net, not neutral.

In other words, an ion is a molecule or atom that has a positive or negative electric charge, making it an atom whose electric charge is not neutral.

The characteristic property of a metallic atom is to lose one or more of its electrons to form a positive ion. That is, metals lose electrons and acquire a net positive charge, which is why they are electropositive.

a chemical reaction

explanation:

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.