1. Neutral Atom:
- Atoms in their neutral state have an equal number of protons (positively charged particles) and electrons (negatively charged particles). This results in a net charge of zero.
2. Electron Gain:
- When an atom encounters an electron, it can potentially gain that electron, especially if the atom has a strong attraction for electrons. This attraction is based on the atom's electronegativity - the tendency of an atom to attract electrons towards itself.
- The added electron fills an empty energy level within the atom's electron shell.
3. Net Negative Charge:
- Since the atom now has more electrons (negative charges) than protons (positive charges), it acquires a net negative charge. This negatively charged atom is now considered a negative ion or anion.
Example:
- A chlorine atom (Cl) has 17 protons and 17 electrons.
- When it gains an electron, it becomes a chloride ion (Cl-), with 17 protons and 18 electrons.
Why do atoms gain electrons?
- Atoms want to achieve a stable electron configuration, usually resembling the nearest noble gas element. Gaining electrons helps them attain a full outer electron shell, making them more stable.
Key Points:
- Negative ions are formed when an atom gains electrons.
- The gain of electrons results in a net negative charge on the atom.
- The process is driven by the atom's desire to achieve a stable electron configuration.
Let me know if you'd like more examples or have any other questions!
