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Which Statement Is True About a Polyatomic Ion?
A polyatomic ion is a charged particle that consists of two or more atoms covalently bonded together. These ions have a net positive or negative charge and can exist independently or as part of a larger compound. Understanding the properties and behavior of polyatomic ions is essential for studying various scientific disciplines, including chemistry and biology. In this article, we will explore the true statements about polyatomic ions and answer some frequently asked questions.
Statement 1: Polyatomic ions can be positively or negatively charged.
This statement is true. Polyatomic ions can carry a positive charge, known as a cation, or a negative charge, known as an anion. The charge arises from the loss or gain of electrons by the atoms within the ion. For example, the ammonium ion (NH4+) carries a positive charge, while the nitrate ion (NO3-) carries a negative charge.
Statement 2: Polyatomic ions can form ionic or covalent bonds.
This statement is also true. Polyatomic ions can participate in both ionic and covalent bonding. In ionic bonding, polyatomic ions with opposite charges attract each other, forming ionic compounds. For instance, the sodium ion (Na+) can bond with the hydroxide ion (OH-) to form sodium hydroxide (NaOH). In covalent bonding, polyatomic ions share electrons with other atoms to form covalent compounds. An example of this is the sulfate ion (SO42-) bonding with four hydrogen atoms to form sulfuric acid (H2SO4).
Statement 3: Polyatomic ions can have complex structures.
This statement is true as well. Polyatomic ions can have intricate structures due to the presence of multiple atoms. These ions can exhibit various shapes, such as linear, trigonal planar, tetrahedral, or octahedral, depending on the arrangement of the atoms. The shape of the ion affects its polarity and overall reactivity.
Statement 4: Polyatomic ions can influence the properties of compounds.
This statement is true and significant. The presence of polyatomic ions can significantly impact the physical and chemical properties of compounds. For instance, the carbonate ion (CO32-) confers basic properties to compounds such as sodium carbonate (Na2CO3). Conversely, the presence of the phosphate ion (PO43-) in compounds like calcium phosphate (Ca3(PO4)2) imparts acidic properties. The properties of these compounds, such as solubility or reactivity, are directly influenced by the polyatomic ions they contain.
FAQs:
Q: How are polyatomic ions named?
A: Polyatomic ions are often named based on their composition and charge. For example, the sulfate ion (SO42-) consists of sulfur and oxygen atoms and carries a charge of -2.
Q: Can polyatomic ions exist independently?
A: Yes, polyatomic ions can exist as independent entities. They can also combine with other ions or atoms to form compounds.
Q: Are polyatomic ions common in nature?
A: Yes, polyatomic ions are prevalent in nature. They are found in various compounds, such as salts, acids, and bases, which are essential for biological and chemical processes.
Q: Can polyatomic ions change their charge?
A: Polyatomic ions typically maintain a consistent charge. However, some ions can change their charge under specific conditions, such as when they undergo chemical reactions.
In conclusion, polyatomic ions are charged particles composed of multiple atoms. They can be positively or negatively charged, form different types of bonds, have complex structures, and influence the properties of compounds. Understanding these true statements about polyatomic ions is fundamental to comprehending their importance in various scientific fields.
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