How does an atom become an anion?

• A. It gains one or more protons, increasing its atomic number.
• B. It gains one or more electrons, giving it a net negative charge.
• C. It loses one or more electrons, giving it a net positive charge.
• D. It loses neutrons, changing only its mass number but not its charge.

Answer: (B)

Verified step by step guidance

1. Understand that an atom consists of protons, neutrons, and electrons. Protons have a positive charge, electrons have a negative charge, and neutrons are neutral.
2. Recall that the atomic number of an element is determined by the number of protons in its nucleus, which does not change when forming ions.
3. Recognize that an anion is an ion with a net negative charge, which means the atom must have more electrons than protons.
4. Know that an atom becomes an anion by gaining one or more electrons, increasing the total negative charge without changing the number of protons.
5. Therefore, the correct process for an atom to become an anion is by gaining electrons, not by gaining protons, losing electrons, or losing neutrons.