Bonding in Polyatomic Ions and Compounds

Summary

The video explains bonding in polyatomic ions and compounds containing them. Polyatomic ions are groups of covalently bonded atoms with a net charge. For example, nitrate (NO3-) consists of a nitrogen atom covalently bonded to three oxygens. In compounds like sodium nitrate, there are both ionic bonds between Na+ and NO3- and covalent bonds within the polyatomic ion. The video further explores how polyatomic ions gain or lose electrons to achieve stable bonds, resulting in their charge, using examples like hydroxide (OH-) and ammonium (NH4+).

Takeaways

• 🔋 Polyatomic ions are groups of atoms bonded together and carry a charge.
• ⚡ Nitrate (NO3 1-) is an example of a polyatomic ion, with nitrogen and oxygen atoms bonded covalently.
• 🧲 In compounds like sodium nitrate (NaNO3), there are two types of bonding: ionic bonding between ions and covalent bonding within the polyatomic ion.
• 🧪 Ionic bonds hold the sodium (Na+) and nitrate (NO3 1-) ions together due to opposite charges.
• 🧬 Covalent bonds hold atoms within polyatomic ions together, like the bonds between nitrogen and oxygen in nitrate.
• 🔍 Polyatomic ions have charges because of the gain or loss of electrons needed to form covalent bonds.
• 🧑‍🔬 Hydroxide (OH-) is a polyatomic ion where oxygen covalently bonds with hydrogen, gaining an extra electron and acquiring a negative charge.
• 🔑 The charge on polyatomic ions, like hydroxide, is due to the extra electron needed for bonding.
• 🔧 Ammonium (NH4 1+) is an example where nitrogen bonds with hydrogen and loses an electron, resulting in a positive charge.
• 🌟 Polyatomic ions form due to the need for atoms to either gain or lose electrons to satisfy their bonding needs, resulting in the charge seen on these ions.

Q & A

What is a polyatomic ion?

A polyatomic ion is a group of atoms bonded together that collectively has a charge. These atoms are held together by covalent bonds, but the entire group functions as a single charged entity.

What type of bonds hold the atoms together in a polyatomic ion?

The atoms within a polyatomic ion are held together by covalent bonds, which involve the sharing of electrons between atoms.

What type of bonding exists between polyatomic ions and other ions in a compound like sodium nitrate?

In compounds like sodium nitrate, there are two types of bonding: ionic bonds between the sodium ion (Na+) and the nitrate ion (NO3−), and covalent bonds holding the atoms together within the nitrate ion.

Why do polyatomic ions have a charge?

Polyatomic ions have a charge because during covalent bonding, the group of atoms either gains or loses electrons to achieve stability. This imbalance in electron count results in either a positive or negative charge.

How does the polyatomic ion nitrate (NO3−) get its charge?

Nitrate (NO3−) has a charge of 1− because, during bonding, the atoms in the ion collectively gain one extra electron to achieve stable electron configurations, giving the ion an overall negative charge.

What happens when an oxygen atom bonds with a hydrogen atom to form hydroxide (OH−)?

In the formation of hydroxide (OH−), the oxygen atom shares electrons with the hydrogen atom to form a covalent bond. However, oxygen needs one more electron to fill its valence shell, so it gains an additional electron, resulting in the hydroxide ion's negative charge.

What is the difference between ionic and covalent bonds in polyatomic ions?

Covalent bonds occur within the polyatomic ion, holding the atoms together by sharing electrons. Ionic bonds occur between the polyatomic ion (which has a charge) and other oppositely charged ions in a compound, where opposite charges attract.

Why does the ammonium ion (NH4+) have a positive charge?

The ammonium ion (NH4+) has a positive charge because during bonding, nitrogen and the four hydrogens share electrons, but they collectively have one extra electron, which they lose. Losing this electron gives the ion a positive charge.

What is the structure of the nitrate ion (NO3−) in terms of bonding?

In the nitrate ion (NO3−), nitrogen is covalently bonded to three oxygen atoms. The ion as a whole has gained an extra electron, which gives it a 1− charge.

How do polyatomic ions like hydroxide (OH−) and ammonium (NH4+) gain or lose electrons?

Polyatomic ions either gain or lose electrons based on the electron requirements of the atoms involved. If the atoms in the ion need additional electrons to achieve stable configurations, they gain electrons (like hydroxide, OH−). If they have excess electrons, they lose them (like ammonium, NH4+).