How are ions made from neutral atoms?
Ions are created when neutral atoms either lose or gain electrons, forming cations and anions, respectively.
Formation of Ions:
Neutral atoms can become ions by either losing or gaining electrons. When a neutral atom loses electrons from its valence shell, it becomes a cation (a positively charged ion). Conversely, when a neutral atom gains electrons in its valence shell, it becomes an anion (a negatively charged ion).
Types of Ions:
There are two main types of ions that can be formed:
- Positive ions (cations): For example, Na+ is formed when sodium atom loses an electron: Na → Na+ + e-
- Negative ions (anions): For example, Cl- is formed when a chlorine atom gains an electron: Cl + e- → Cl-
Charges of Ions and Ionic Compounds:
The periodic table can help predict the charges of ions based on their group. Different groups of elements tend to form ions with specific charges. For example:
- Alkali metals (Group 1) typically form +1 cations.
- Alkaline earth metals (Group 2) typically form +2 cations.
- Halogens (Group 17) typically form -1 anions.
The combination of oppositely charged ions leads to the formation of ionic compounds. The ratio of positive and negative ions in an ionic compound is such that their charges balance out, resulting in a compound that is electrically neutral.
Electron Configurations and Ion Charges:
It is essential to understand that ions form as a result of the movement of electrons, not protons. The number of valence electrons in an atom plays a crucial role in determining the common ion charge for elements within the same group on the periodic table. By either losing or gaining electrons to achieve a stable electron configuration, atoms can form ions.