When electrons are lost, a ion is formed. when electrons are gained, a ion is formed.

When electrons are lost, a positively charged ion is formed. When electrons are gained, a negatively charged ion is formed.

Explanation:

Atoms consist of three particles:

- Protons, positively charged, in the nucleus

- Neutrons, no charge, in the nucleus

- Electrons, negatively charged, orbiting around the nucleus

The proton and the electron have same magnitude of charge (), but the proton's charge is positive while the electron's charge is negative.

For a neutral atom, the number of protons is equal to the number of electrons, so the atom is electrically neutral. However, sometimes the atom can lose or gain electrons, becoming electrically  charged: this is called ion. In particular:

- If the atom loses one (or more) electrons, it will remain with an excess of positive charge (because the number of protons is now greater than the number of electrons), so it will form a positively charged ion

- if the atom gains one (or more) electrons, it will remain with an excess of negative charge (because the number of protons is now smaller than the number of electrons), so it will form a negatively charged ion

answer///scientific method;