What is an atom or group of atoms with an electric charge called

Ion

Explanation:

An atom is generally neutral, since its number of protons in the nucleus is equal to the number of electrons around the nucleus: since proton and electrons have opposite charge (but equal in magnitude), the total charge of the atom is zero.

However, sometimes atoms can gain or lose electrons: when this happens, they are called ions. In particular:

- When an atom loses one (or more) electrons, it remains with an excess of positive charge, so it is called positive ion

- When an atom gains one (or more) electrons, it remains with an excess of negative charge, so it is called negative ion

- measure reactants precisely. ( first choice)

- stir to the reaction take place. ( second choice)

- wait patiently until the reaction completes. ( fourth choice)

- make sure to recover as much copper as possible. ( last choice)