What Are Covalent Bonds | Properties of Matter | Chemistry | FuseSchool

Summary

This video script explains covalent bonding, where atoms share electrons to form bonds, commonly seen between non-metals. It distinguishes covalent bonds from ionic bonds and highlights their directional nature. The script also covers single, double, and triple bonds, and contrasts small covalent molecules with giant covalent structures like diamond. It concludes with a challenge to identify covalent compounds based on their physical properties and periodic table positions.

Takeaways

• 🔬 Covalent bonds are formed when atoms share electrons, typically between non-metal elements.
• 🌐 Non-metals, found on the right and upper part of the periodic table, prefer sharing electrons due to their partially filled valence shells.
• 🔗 Covalent bonds can be single, double, or triple, depending on the space available in the outer shell of the atom.
• 📐 Covalent bonds are directional, unlike ionic bonds which are formed by electrostatic attraction between charged particles.
• 👥 Non-metal atoms share electrons by overlapping orbitals, creating a bonding orbital that contains two electrons.
• 📚 Covalent bonds are represented in chemical formulas with straight lines or dot and cross diagrams, which show only the valence electrons.
• 💧 Small molecules like water and giant compounds like diamond are examples of covalent structures.
• 🔥 Compounds with covalent bonds have low melting and boiling points and are non-conductive because the electrons are evenly shared.
• 💎 Diamond is an example of a giant covalent structure where each carbon atom forms four covalent bonds.
• 🌐 Allotropes of non-metals, like carbon and silicon, bond covalently and can form different structures of the same element.

Q & A

What is a covalent bond?

A covalent bond is a type of chemical bond formed between non-metal atoms where electrons are shared rather than transferred.

How do atoms form covalent bonds?

Atoms form covalent bonds by overlapping their orbitals to share electrons, creating a bonding orbital that contains two electrons.

Why do non-metals typically form covalent bonds?

Non-metals form covalent bonds because they have a strong attraction for a few additional electrons and it is energetically unfavorable for them to lose electrons.

Where on the periodic table are non-metals found?

Non-metals are found on the right-hand side and upper part of the periodic table.

What are some common non-metal elements that form covalent bonds?

Some common non-metal elements that form covalent bonds include carbon, nitrogen, oxygen, and the halides.

How are covalent bonds represented in chemical formulas?

Covalent bonds are represented in chemical formulas with straight lines, where each line represents a pair of shared electrons.

What is a dot and cross diagram?

A dot and cross diagram is a way to represent covalent bonds that shows only the valence electrons of the atoms involved in the bond.

Are covalent bonds directional?

Yes, covalent bonds are directional, meaning they have a fixed position and orientation, unlike ionic bonds which are formed through electrostatic attraction.

What is the difference between small covalent molecules and giant covalent compounds?

Small covalent molecules are individual molecules like water, while giant covalent compounds form extensive lattices or chains, like diamond, where each atom is covalently bonded to many others.

Why do compounds made from small covalent molecules have low melting and boiling points?

Compounds made from small covalent molecules have low melting and boiling points because the forces holding them together are weak intermolecular forces, not the stronger covalent bonds.

How does the structure of a giant covalent compound like diamond affect its properties?

The structure of a giant covalent compound like diamond results in very high melting and boiling points because the atoms are held rigidly in place by strong covalent bonds throughout a large lattice.

What are allotropes and how are they related to covalent bonding?

Allotropes are different structural forms of the same element. They bond covalently, and examples include different forms of carbon like graphite and diamond.

Outlines

00:00

🔬 Covalent Bonding Basics

This paragraph introduces covalent bonds, explaining how they are formed through the sharing of electrons between atoms, particularly non-metals. It contrasts covalent bonding with ionic bonding, which involves the transfer of electrons between very different atoms like metals and non-metals. The paragraph also discusses the directional nature of covalent bonds and their strength due to the close proximity of atoms. It mentions the representation of covalent bonds in compounds and the types of structures formed, such as small molecules like water and giant compounds like diamond. The properties of covalent compounds, like low melting and boiling points and non-conductivity, are highlighted. The paragraph concludes with a challenge for the viewer to identify covalent compounds based on their physical properties and periodic table positions.

05:01

🌐 Examples of Covalent Compounds

The second paragraph provides examples of covalent compounds, including small molecules like carbon dioxide, carbon monoxide, and methanol, as well as organic molecules that form covalent bonds between hydrogen and carbon. It also mentions C70, a fullerene molecule, and silicon dioxide, a giant covalent structure similar to diamond but with oxygen atoms bridging silicon atoms. The paragraph aims to reinforce the viewer's understanding of identifying covalent compounds and recognizing their properties.

Keywords

💡Covalent Bonds

Covalent bonds are a type of chemical bond formed when two atoms share one or more pairs of electrons. In the video, covalent bonds are the central theme, explaining how they are formed between similar atoms, such as non-metals, through the sharing of electrons rather than swapping or transferring them as in ionic bonds. Examples from the script include the formation of covalent bonds in molecules like oxygen and nitrogen, which can form double or triple bonds.

💡Valence Shell

The valence shell is the outermost electron shell of an atom, which is involved in chemical bonding. The video mentions that all elements except noble gases have partially filled valence shells, making them capable of bonding with other atoms to complete these shells. This concept is crucial for understanding why covalent bonding occurs.

💡Non-Metals

Non-metals are elements found on the right-hand side and upper part of the periodic table. The video explains that non-metals tend to form covalent bonds with each other by sharing electrons due to their partially filled valence shells. Examples given include carbon, nitrogen, oxygen, and halides.

💡Electron Sharing

Electron sharing is the process by which two atoms become bonded through the sharing of electrons. The video emphasizes that non-metals share electrons by overlapping orbitals to form covalent bonds, which is a key mechanism in covalent bonding.

💡Bonding Orbital

A bonding orbital is the space where the shared electrons of a covalent bond reside. The video describes how the overlap of atomic orbitals creates a bonding orbital that contains two electrons, which is the essence of a covalent bond.

💡Double and Triple Bonds

Double and triple bonds are covalent bonds involving two or three shared electron pairs, respectively. The video mentions that non-metal atoms with space in their outer shell can form these multiple bonds, as seen in molecules like oxygen (O=O) and nitrogen (N≡N).

💡Covalent Bond Representation

The video explains two ways to represent covalent bonds: with straight lines in chemical formulas and with dot and cross diagrams that show only the valence electrons. These representations are important for visualizing and understanding the structure of covalently bonded molecules.

💡Directionality

Directionality refers to the fixed position and orientation of covalent bonds, likened to holding hands. The video contrasts this with ionic bonds, which are formed through electrostatic attraction between charged ions and do not have a fixed direction. This property contributes to the strength and specificity of covalent bonds.

💡Giant Covalent Compounds

Giant covalent compounds are large networks of covalently bonded atoms, like diamond or silicon dioxide. The video explains that these compounds are formed by atoms like carbon and silicon that form four covalent bonds, creating extensive, rigid structures with high melting and boiling points.

💡Allotropes

Allotropes are different structural forms of the same element that bond covalently. The video mentions that allotropes can be found among non-metals and gives examples like diamond and graphite for carbon, illustrating the diversity in bonding and structure that can occur with covalent bonding.

💡Polarization

Polarization refers to the uneven distribution of electron density in a bond, which can occur in covalent bonds. The video notes that in compounds made from small covalent molecules, the bonds are not polarized, leading to weak intermolecular forces and low melting and boiling points.

Highlights

Covalent bonds are formed by the sharing of electrons between atoms.

Non-metals typically form covalent bonds by sharing electrons.

Non-metals are found on the right-hand side and upper part of the periodic table.

Examples of common non-metals include carbon, nitrogen, oxygen, and halides.

Non-metals have partially filled valence shells, making them reluctant to lose electrons.

Covalent bonds involve the overlapping of orbitals to form a bonding orbital.

Covalent bonds can be single, double, or triple, depending on the space in the outer shell.

Covalent bonds are represented by straight lines in chemical formulas.

Dot and cross diagrams are used to represent valence electrons in covalent bonds.

Covalent bonds are directional, unlike ionic bonds which are formed by electrostatic attraction.

Atoms in covalent bonds are very close due to the overlap between orbitals.

Covalent bonds are strong because electrons are evenly shared.

Small covalent molecules have low melting and boiling points and are volatile.

Giant covalent compounds, like diamond, have high melting and boiling points.

Carbon and silicon tend to form giant covalent compounds.

Diamond is an example of a giant covalent structure made of carbon.

Allotropes of non-metals bond covalently and can have different structures.

Covalent compounds can be identified by their physical properties and the elements' positions on the periodic table.

Examples of covalent compounds include carbon dioxide, carbon monoxide, methanol, and C70.

Silicon dioxide is a giant covalent structure similar to diamond but with oxygen atoms.

Transcripts

covalent bonds in this video you are

going to learn about covalent bonds how

they are made and how they form

if you haven't seen it already first

have a look at our video structure and

bonding

only the noble gases exist naturally as

single atoms

all the other elements of the periodic

table have partially filled valence

shells or outer electron shells

atoms bond by swapping or sharing

electrons in their outer shells

when very different atoms react like

metals and non-metals they normally swap

electrons

this is ionic bonding

but when similar atoms react like

non-metals combining with other

non-metals they share electrons this is

covalent bonding

non-metals are found on the right hand

side and upper part of the periodic

table

some common non-metals are carbon

nitrogen oxygen

and the halides

they have shells of electrons that are

normally half or more than half full of

electrons

since they have a strong attraction for

a few additional electrons it is

energetically unfavorable for them to

lose electrons

so they share electrons by overlapping

orbitals

this makes a bonding orbital or covalent

bond

that contains two electrons

if there is space in the outer shell a

non-metal atom can form double or triple

bonds like in oxygen or nitrogen

in the displayed formula of a compound

we represent a covalent bond with a

straight line

like this

we can also represent a covalent bond as

a dot and cross diagram

these diagrams show only the valence

electrons

to learn more about dots and cross

diagrams watch our video on dos and

cross diagrams

covalent bonds are directional which

means they are in a fixed position like

holding hands

this is different from ionic bonds which

are formed with an electrostatic

attraction between charged ions

the overlap between orbitals means that

the atoms in covalent bonds are very

close

these things make covalent bonds strong

there are two kinds of covalent

structure

small molecules like water and giant

compounds like diamond

because the electrons in the bonds are

evenly shared bonds are not polarized

there is little attraction between

molecules and forces between molecules

are weak

compounds made from small covalent

molecules have low melting and boiling

points and are volatile

they also don't conduct electricity

carbon and silicon tend to form giant

covalent compounds

these bond in the same way

but instead of forming small molecules

with one or two bonds they form four

making up huge lattices or chains of

many many linked up atoms the basis of

the organic chemistry of carbon or the

chemistry of rocks

one common example is diamond which is

made of carbon

each carbon atom forms four covalent

bonds because it has four electrons in

its outer shell to share and has space

for four more

if every carbon atom forms four bonds

with four other carbon atoms and each of

these forms four bonds with four other

carbon atoms and each of these forms

four bonds we very quickly end up with a

very large structure

these compounds have very high melting

and boiling points because you have to

break covalent bonds rather than

intermolecular forces to make them free

enough to act as liquids or gases

the covalent bonds hold them rigidly in

place in the giant lattice

allotropes of non-metals bond covalently

allotropes are different structures of

the same element

you can learn more about these in our

video allotropes of non-metals

so to finish here's the challenge for

you

which of these compounds are covalent

pause the video for a moment whilst you

think

have you considered their physical

properties and where the elements come

from on the periodic table

solved it

okay

the answer is all of these compounds are

covalent

carbon dioxide carbon monoxide and

methanol are all small molecules

organic molecules form covalent bonds

between hydrogen and carbon

c70 is a fullerene

a carbon molecule shaped like a rugby

ball closely related to the buckminster

fullerene

silicon dioxide is a giant covalent

structure and just like diamond but has

oxygen atoms bridging between four

coordinate silicon atoms

hopefully you now feel confident

identifying covalent compounds and

recognizing their properties