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+).

Outlines

00:00

🔬 Understanding Polyatomic Ions and Their Bonding

This paragraph introduces polyatomic ions, which are groups of atoms bonded together that carry a charge. Using nitrate (NO3-) as an example, the explanation highlights how the atoms in a polyatomic ion are held together by covalent bonds. The nitrogen and oxygen atoms form a 'clump' through covalent bonding, but the overall structure has a charge, which is why polyatomic ions behave the way they do. The sodium nitrate (NaNO3) example illustrates how compounds with polyatomic ions have both ionic and covalent bonding—ionic bonding between Na+ and NO3-, and covalent bonding within the NO3- ion.

05:02

⚛️ Why Polyatomic Ions Have a Charge

This paragraph explores the reason polyatomic ions carry a charge. It explains how covalent bonding and valence electrons are key factors. Using an oxygen-hydrogen example, it shows that sometimes atoms in a polyatomic ion don’t have enough electrons to satisfy their bonding needs, leading them to 'steal' electrons from the environment. When this happens, the entire polyatomic ion acquires a charge. In this case, by gaining an electron, the molecule (hydroxide, OH-) becomes negatively charged. The explanation is supported by using electron dot diagrams and Lewis structures to visualize this process.

10:04

🧪 The Role of Extra Electrons in Polyatomic Ions

This section provides a deeper example of how polyatomic ions either gain or lose electrons to maintain bonding stability. Using a nitrogen and hydrogen (NH4+) example, it explains how atoms that don’t need extra electrons will 'throw away' the excess, which results in a positive charge for the polyatomic ion. This is how the ammonium ion (NH4+) gets its 1+ charge. By walking through the math of valence electrons and electron distribution, the paragraph reinforces the concept that polyatomic ions gain or lose electrons to satisfy covalent bonding requirements.

Keywords

💡Polyatomic ion

A polyatomic ion is a group of atoms covalently bonded together that carries an overall charge, either positive or negative. In the video, examples such as nitrate (NO3−) and hydroxide (OH−) are used to illustrate that these ions form from atoms that share electrons but have an overall imbalance in the number of protons and electrons, leading to a net charge. Polyatomic ions are crucial for understanding the bonding in compounds like sodium nitrate.

💡Covalent bond

A covalent bond is a type of chemical bond where atoms share pairs of electrons to achieve a stable electron configuration. In the video, covalent bonds are described as the 'glue' that holds atoms like nitrogen and oxygen together in polyatomic ions. Covalent bonding is essential in forming the stable clumps of atoms that make up polyatomic ions like nitrate (NO3−).

💡Ionic bond

An ionic bond occurs when oppositely charged ions attract each other due to electrostatic forces. The video explains that ionic bonds hold together ions like Na+ and NO3− in compounds such as sodium nitrate. While the individual atoms in polyatomic ions are held together by covalent bonds, the entire ion itself forms ionic bonds with other charged particles.

💡Nitrate (NO3−)

Nitrate is a polyatomic ion with the formula NO3−, composed of one nitrogen atom and three oxygen atoms held together by covalent bonds. The video uses nitrate as an example to explain how a group of atoms can collectively carry a negative charge, which is then attracted to positively charged ions (like Na+ in sodium nitrate).

💡Lewis structure

A Lewis structure is a diagram that represents the valence electrons of atoms within a molecule or polyatomic ion. In the video, Lewis structures are used to visualize how atoms share electrons to form covalent bonds, as seen in the hydroxide ion (OH−) and ammonium ion (NH4+). These diagrams help explain the distribution of electrons and the resulting charges on the ions.

💡Valence electrons

Valence electrons are the outermost electrons of an atom that are involved in bonding. The video emphasizes that counting valence electrons is key to understanding how atoms form bonds, particularly in polyatomic ions. For example, oxygen has six valence electrons, and hydrogen has one, and their combination in hydroxide leads to electron sharing that results in a negative charge.

💡Electron dot diagram

An electron dot diagram is a representation of an atom's valence electrons, shown as dots around the element's symbol. These diagrams are useful for visualizing the bonding between atoms, as seen in the video's explanation of how oxygen and hydrogen form the hydroxide ion (OH−). The dots help track electron sharing and the formation of covalent bonds.

💡Ammonium (NH4+)

Ammonium is a polyatomic ion with the formula NH4+, consisting of one nitrogen atom and four hydrogen atoms. The video explains that ammonium forms when nitrogen shares electrons with hydrogen atoms and loses an extra electron, resulting in a positive charge. Ammonium is an example of a polyatomic ion where covalent bonding and the loss of an electron lead to an overall charge.

💡Charge

Charge refers to the electrical imbalance in an ion due to the gain or loss of electrons. The video discusses how polyatomic ions like nitrate (NO3−) and ammonium (NH4+) acquire their charges—either by gaining extra electrons (negative charge) or losing electrons (positive charge). Understanding charge is key to explaining the behavior of ions in compounds and their bonding mechanisms.

💡Sodium nitrate (NaNO3)

Sodium nitrate is an example of an ionic compound containing a polyatomic ion, composed of Na+ and NO3−. The video uses sodium nitrate to illustrate how polyatomic ions participate in both covalent and ionic bonding. The nitrate ion is held together by covalent bonds, while the overall compound is stabilized by the ionic attraction between Na+ and NO3−.

Highlights

Polyatomic ions are clusters of atoms held together by covalent bonds and have an overall charge.

Nitrate (NO3 1-) consists of one nitrogen atom and three oxygen atoms, held together by covalent bonds.

In sodium nitrate (NaNO3), both ionic and covalent bonds exist: ionic bonds between Na+ and NO3-, and covalent bonds within the NO3-.

Polyatomic ions like NO3- have both ionic and covalent bonds in the compound.

The charge on polyatomic ions is due to gaining or losing electrons to satisfy the octet rule in covalent bonding.

In hydroxide (OH-), oxygen and hydrogen atoms are covalently bonded, but the ion has an overall negative charge due to gaining one electron.

Polyatomic ions gain or lose electrons to balance their charge during covalent bonding.

In hydroxide (OH-), the additional electron gives it a -1 charge because oxygen needs one more electron to complete its valence shell.

In ammonium (NH4+), nitrogen is covalently bonded to four hydrogen atoms, but the ion has a positive charge due to losing one electron.

Ammonium (NH4+) has a +1 charge because the group of atoms loses an electron, making the nitrogen and hydrogen atoms 'happy' with their electron configuration.

Covalent bonds in polyatomic ions are responsible for holding the atoms together within the ion.

Ionic compounds with polyatomic ions, like NaNO3, involve both ionic bonds (between ions) and covalent bonds (within polyatomic ions).

The charge of polyatomic ions arises from the need to satisfy the atoms' electron configurations by gaining or losing electrons.

In ammonium (NH4+), nitrogen and hydrogen share electrons via covalent bonds, but the ion loses an electron, resulting in a positive charge.

Polyatomic ions can have either positive or negative charges based on whether they gain or lose electrons during bonding.

Transcripts

let's talk about bonding in polyatomic

ions and compounds that have polyatomic

ions in them so a whole bunch of

polyatomic ions this is just a small

list of some of them but they all share

one thing in common and that's that they

all are a bunch of atoms connected

together in a clump and that Clump then

has a charge okay that's what a

polyatomic ion

is let's take nitrate here NO3 1 minus

and we can draw the atoms in nitrate

like this one nitrogen and three oxygen

and this whole thing is surrounded by

brackets because it has a charge of 1

minus so nitrogen and those these three

oxygens they're a clump together okay

but what's holding the oxygens together

with the nitrogen right what's the glue

that connects these atoms together it is

actually Cove valent bonds that are

attaching the Oxygen's uh together with

the nitrogen so there is a coent bond

here a calent bond here and a calent

bond here keeping this clump of atoms

together so this is a little bit tricky

because it means that in a compound like

sodium

nitrate there are two types of bonding

going on okay there's ionic bonding

because opposite charges are attracting

okay because na can take a charge of 1

plus and NO3 as you can see right from

the list here has a charge of 1 minus

okay so the na and the NO3 are stuck

together because of ionic bonds here let

me show you what I

mean so here's the na+ and here's the

NO3 1 minus and these guys want to stick

together because they have opposite

charges so it's an ionic bond here

that's holding this whole Clump together

with this ion na+ here okay ionic bond

that's what I'm referring to here is the

attraction between these two things so

they're ionic bonds holding the positive

thing together with a negative thing but

then there are Cove valent bonds that

are holding all of the atoms together in

this clump of atoms that's nitrate okay

so uh an ionic compound with polyatomic

ions in it has both ionic bonds and

calent bonds okay now I want to address

another

question I want to explain

why polyatomic ions have a charge okay

now this has to do with coent bonding Le

structures electron dot diagrams and

some similar things veence electrons for

example if you don't know a lot about

these already no big deal you can turn

the video off and maybe you can watch it

later when you do understand these

things but if you already have a

background and this kind of stuff you

might be interested in how these clumps

of atoms actually get a charge in the

first place okay so as I

said it's all about coent bonding for

holding the atoms together in these

polyatomic compounds I mean for for

holding them together in these

polyatomic clumps okay so let's take an

example and see how the calent bonding

holding them together causes them to

have a

charge let's say that an oxygen atom

wants to come together with one hydrogen

atom I want to look at how the calent

bonding is going to work so I'm going to

want to draw a leis structure okay so in

order to draw a Luis structure I want to

find out how many veence electrons there

are in both of the atoms that I'm

working

with hydrogen is in this First Column

here so it has one veence electron to

find out how many valence electrons

oxygen has I can count 1 two 3 4 5 6 so

oxygen has six valence

now when I'm drawing the Lewis structure

I add these two up so I have seven total

veence electrons that oxygen and

hydrogen can share together okay so

here's the first step I'm going to take

oxygen and I'm going to draw it next to

hydrogen and now I'm going to take my

seven electrons here they are and I'm

going to arrange them around oxygen and

hydrogen so that both atoms have full

valence

shells oxygen wants to have eight

electrons but hydrogen is happy with

only two veence electrons in its outer

shell okay so let me do this put a

couple around oxygen like this put two

here for hydrogen to be

sharing and this is what I get but this

is a problem okay because oxygen wants

to have eight but it only has 1 2 3 4 5

6 7 here hydrogen is Happy it has a two

that it wants but oxygen is really

pissed wants one more but it only has

seven total to distribute between these

two atoms so what can we do here well

this oxygen and hydrogen pair they can

steal an electron from somewhere else

and that's exactly what they do here it

is they pull this electron in from

elsewhere and we can say that it gains

one electron they needed this one more

electron in order to make the bonding

work okay but they gained an El and what

happens if you gain an electron you get

a negative charge so by pulling in this

one extra electron to make the bonding

work now this clump of atoms the oxygen

and the hydrogen that are coent bonded

together now they have a charge okay we

can convert this electron dot diagram

into a proper calent bonding diagram

here where I replace the shared pair

with a line okay that means they're

sharing two electrons and then I put

these dots for unshared pairs around the

oxygen and now I put the whole thing in

Brackets with a minus this is what it

looks like and this is a polyatomic ion

okay we call this

hydroxide and its formula is o1 minus

just once again it's an O coal bonded to

an H but in order for this coent bond to

work out in order for both atoms to be

happy they had to grab an additional

electron from the environment and in

gaining that extra electron to make

everything work the whole Clump got a

one minus charge let me show you another

example let's say that one

nitrogen is going to come together with

four

hydrogens let's do the math to figure

out how we're going to draw the Lewis

structure hydrogen is in this First

Column so one one one one each one of

these hydrogens has one veence electron

to donate 1 2 3 4 5 nitrogen is in this

fifth column here so it has five valence

electrons now I want to find out the

total number that we have 5 + 1 + 1 + 1

plus one I lost count of how many I was

doing nine total electrons okay let's

draw the Dot Structure for this nitrogen

is um I only have one nitrogen so

chances are very high that it's going to

be the middle atom I'm going to put that

in the middle and then I'm going to

arrange the hydrogens around it okay so

now I have nine nine electrons to

distribute between these atoms so that

they're all happy nitrogen is going to

want have eight electrons in its outer

valence shell and hydrogen it's happy

with two okay so let's do that we've got

nine electrons to distribute to make all

of these atoms happy

here and if I put an electron between

two atoms it means that those two

electrons are it means that those two

atoms are sharing the electrons and that

a calent bond is formed between them so

here's what we have we have eight

electrons distributed around nitrogen

each of the hydrogens are sharing two

electrons with nitrogen so everything's

happy but I have an additional electron

because you add up all the veence

electrons you get nine so here's a ninth

electron but these guys the nitrogen and

the hydrogen they're like we're already

happy right we we have everything that

we need nitrogen has eight each of the

hydrogen have two they're like What's

the deal here we don't know what to do

with you what are we going to do with

this ninth

electron they Chuck it out they throw it

away so they take this ninth electron

and in order you know for all of them to

be happy they're like get out of here

and they throw it away okay so they

lose one electron this group of atoms

loses an electron if you gain an

electron you get a negative charge if

you lose an electron what happens to you

you get a positive

charge

so this whole thing has just become a

polyatomic ion because it's a clump of

atoms coal bonded together that has a

charge it looks like this if you want to

uh draw the calent bonds between them

with a one plus and we call this

ammonium you might be familiar with it

because it's one of the polyatomic ions

that's on my list ammonium NH

h41 plus just once again it gets this

charge because it has nine total

electrons but it only needs eight is

that eight yeah it only needs eight I'm

really bad with counting it only needs

eight and so it needs to get rid of that

ninth electron and in doing so it loses

it and it gets a positive charge so

there are all these polyatomic ions that

we've talked about as I keep saying just

a small number of them on my list here

but all of them are clumps of atoms held

together with calent bonds and they all

have charges and as you've just learned

the reason why they have charges is

because in order to make the Cove valent

bonds work between these atoms they

either have to gain electrons or they

have to lose electrons and so that's why

these polyatomic ions have a charge to

gain or lose electrons to make the

calent bonding work