Clusters of atoms that act as an ion are called:
Polyatomic ions
Understanding Ions and Atomic Clusters
An ion is a charged species. It can be a single atom that has gained or lost electrons, or it can be a group of atoms that are bonded together and collectively carry a charge.
What are Atomic Clusters?
A cluster of atoms simply means two or more atoms bonded together. When such a cluster of atoms behaves as a single unit and carries a net positive or negative charge, it is called an ion.
Analyzing the Options
Let's look at the different types of ions based on the number of atoms they contain:
- Monoatomic ions: These are ions formed from a single atom. Examples include <code>Na+</code> (sodium ion) or <code>Cl-</code> (chloride ion).
- Diatomic ions: These are ions formed from two atoms bonded together, where the cluster of two atoms carries a charge. Examples are less common as isolated species in simple salts but exist, e.g., <code>O22-</code> (peroxide ion).
- Triatomic ions: These are ions formed from three atoms bonded together, where the cluster of three atoms carries a charge. An example is <code>NO2-</code> (nitrite ion).
- Polyatomic ions: The prefix 'poly-' means 'many'. These are ions formed from a cluster of two or more atoms bonded together, where the entire cluster carries a net charge. This is a general term that includes diatomic and triatomic ions, as well as ions with more than three atoms.
Identifying the Correct Term
The question asks for the term used for "clusters of atoms that act as an ion". A cluster of atoms involves more than one atom. Out of the given options:
- Monoatomic refers to a single atom.
- Diatomic refers to two atoms.
- Triatomic refers to three atoms.
- Polyatomic refers to multiple (two or more) atoms.
Since a cluster implies more than one atom, the term that encompasses all clusters of atoms acting as an ion (whether 2, 3, or more atoms) is 'Polyatomic ions'. Diatomic and triatomic ions are specific types of polyatomic ions.
| Type of Ion | Number of Atoms | Example |
|---|---|---|
| Monoatomic | One | <code>Na+</code>, <code>Cl-</code> |
| Diatomic | Two | <code>O22-</code> |
| Triatomic | Three | <code>NO2-</code> |
| Polyatomic | Two or more (a cluster) | <code>SO42-</code>, <code>NH4+</code>, <code>CO32-</code> |
Therefore, the term that correctly describes clusters of atoms that act as an ion is Polyatomic ions.
Revision Table: Ion Types Summary
| Term | Definition | Example |
|---|---|---|
| Ion | A charged atom or group of atoms | <code>K+</code>, <code>OH-</code> |
| Monoatomic Ion | Ion from a single atom | <code>Ca2+</code>, <code>F-</code> |
| Polyatomic Ion | Ion from a cluster of 2+ atoms bonded together | <code>PO43-</code>, <code>CN-</code> |
Additional Information on Polyatomic Ions
Polyatomic ions are very common in chemistry, especially in the study of salts, acids, and bases. They are held together by covalent bonds within the ion, but the ion as a whole participates in ionic bonding with other ions. For example, sodium sulfate (<code>Na2SO4</code>) is formed by ionic bonds between two sodium ions (<code>Na+</code>) and one sulfate ion (<code>SO42-</code>). The sulfate ion itself is a cluster of one sulfur atom and four oxygen atoms bonded covalently, with the entire cluster carrying a 2- charge.
Understanding polyatomic ions is crucial for writing chemical formulas and naming compounds.
Important Questions from Structure of Atom
According to J.J. Thomson model of atom, positive charge is - Idenfity
Ions differ from their corresponding atoms in
- How many moles of He atoms are present in its 20 u mass ?
Which of the following electron transition in hydrogen atom will require largest amount of energy?
A species having 8 electrons in the third shell is very reactive while the other species having 8 electrons in the third shell is very inactive they are :
