Question

a. What are monatomic ions? b. Give three examples of monatomic ions.

Short answer

Monatomic ions are single atoms with a positive or negative charge. Examples include Na⁺, Ca²⁺, Al³⁺ for cations and Cl⁻, O²⁻, N³⁻ for anions.

Step-by-step solution

Understanding Monatomic Ions

Monatomic ions are ions consisting of a single atom that has lost or gained one or more electrons. They carry a net positive or negative electric charge.

Characteristics of Monatomic Ions

These ions have charges due to an imbalance between the number of protons and electrons. If an atom loses electrons, it becomes a positively charged cation. If it gains electrons, it becomes a negatively charged anion.

Examples of Monatomic Cations

Examples of monatomic cations include: 1. Sodium ion \((\text{Na}^+)\) 2. Calcium ion \((\text{Ca}^{2+})\) 3. Aluminum ion \((\text{Al}^{3+})\)

Examples of Monatomic Anions

Examples of monatomic anions include: 1. Chloride ion \((\text{Cl}^-)\) 2. Oxide ion \((\text{O}^{2-})\) 3. Nitride ion \((\text{N}^{3-})\)

Key concepts

Cations

Cations are positively charged ions that form when an atom loses one or more electrons. This loss of negatively charged electrons results in a net positive charge for the atom. The number of positive protons in the nucleus of the atom remains unchanged, which is why the resulting ion carries a positive charge. Common examples of monatomic cations include:

• Sodium ion \((\text{Na}^+)\)
• Calcium ion \((\text{Ca}^{2+})\)
• Aluminum ion \((\text{Al}^{3+})\)

Cations are typically metals, which have a tendency to lose electrons easily. Understanding cations helps in grasping how materials conduct electricity and in predicting the behavior of elements during chemical reactions.

Anions

Anions are negatively charged ions that form when an atom gains one or more electrons. The extra electrons increase the total negative charge, outweighing the number of positive protons in the atom's nucleus. This imbalance gives the atom a net negative charge. Examples of monatomic anions include:

• Chloride ion \((\text{Cl}^-)\)
• Oxide ion \((\text{O}^{2-})\)
• Nitride ion \((\text{N}^{3-})\)

Generally, non-metals form anions because they tend to gain electrons to complete their outer electron shells. Recognizing anions is crucial for understanding many chemical processes, including acid-base reactions and the formation of salts.

Ion Charge

The charge of an ion is determined by the difference between the number of protons and electrons in the atom. If the atom has more protons than electrons, it will be positively charged and form a cation. Conversely, if it has more electrons than protons, it will be negatively charged and form an anion.
To find the charge of a given ion, subtract the number of electrons from the number of protons:
Ion Charge = Number of Protons - Number of Electrons
This concept is pivotal when balancing chemical equations and understanding the properties of ionic compounds. Knowing the charges of common ions can help predict how atoms will interact to form stable compounds.