Chemical Bonds - Online Tutor, Practice Problems & Exam Prep

Chemical bonds are the forces that hold atoms or ions together in a compound, driven by the desire of elements to attain a filled outer shell similar to noble gases. Ionic bonding involves the transfer of electrons from metals, which tend to lose electrons, to nonmetals, which tend to gain them, resulting in a compound like sodium chloride. This process is exothermic, releasing energy and forming an ionic solid. Covalent bonding occurs between nonmetals that share valence electrons to fill their outer shells, creating single or double bonds, as seen in molecules like chlorine or oxygen. Metallic bonding, distinct from ionic and covalent, involves the attraction between free-floating valence electrons and the positively charged ions of a metal's surface, giving metals their malleability and conductivity. These bonding types are fundamental to understanding the structure and properties of different substances in chemistry.

Chemical Bonds

Chemical bond can be seen as the attractive force that holds atoms or ions together in a chemical compound. Now the driving force of these types of chemical bonds we're going to say when elements bond, they're either trying to lose, gain or share electrons to attain a filled outer shell like the noble gases.

Remember, the noble gases are perfect. All the elements that are not noble gases will do things in order to achieve the same type of electron arrangements as these noble gases. This is the driving force behind chemical bonds.

And the next series of videos, we'll see the different types of chemical bonds exist and see do they lose, gain, or share electrons to attain the same kind of configuration as our noble gases.

Chemical Bonds

Now, ionic binding represents a type of chemical bonding. Here the attractive force is between the opposing charges of a cation which is positive and an anion which is negative. We're going to say here, recall that metals tend to lose their valence electrons, and nonmetals tend to gain electrons.

We're going to say here that ionic bonding itself, the ionic bond formation, helps to lower the potential energies of the cation and the anion. This lowering of energy basically entails them releasing their excess energy. This releasing of energy can be thought of as an exothermic reaction. So when we talk about thermochemistry and we're talking about the releasing of energy, we use the term exothermic.

So if we take a look here, we have sodium and we have chlorine. Sodium is a metal. Sodium will want to give away its electron so that it becomes Na+ and becomes more like a noble gas. So it gave up its electrons. So now it's Na+. Chlorine has its seven original electrons and it just gained that electron from sodium. So now it has one additional electron and that gives it a Cl- charge.

If there are opposing charges. Remember opposites attract their opposing charges is what makes them attracted to one another. So because of this they will combine together to give me sodium chloride as my ionic solid. So just remember when it comes to my ionic bond, we first have to have the transferring of the electron from the metal to the non-metal to create opposing charges. Those opposite charges cause the ions to combine together to form my ionic compound at the end.

Chemical Bonds Example 1

Here we're asked which of the following species has bonds with the most ionic character. So think about it. When we talk about ionic bonding, we said it's the opposing charges of a cation and an anion. Remember the cation which is positive is usually a metal. It can also be the ammonium ion. And then remember our anion, our negative ion will be a nonmetal.

These are the fundamental definitions we talked about way back when we first covered ionic compounds versus covalent compounds. So if you don't remember that, good idea to write this down. So basically the most ionic character will be the one that fits this definition of a cation bonded to an anion. So we're looking for an example that has either a metal connected to a nonmetal or the ammonium ion connected to a nonmetal.

And if we look at our choices present, we see that the only choice has to be option C because here it has tin, which is Sn, or metal connected to oxygen, a nonmetal. So we have in this example a metal to a nonmetal. All the others don't fit the criteria to be an ionic compound because they're just nonmetals connected together. They themselves would just represent covalent compounds.

The strength of an ionic bond comes principally from:

• A. The converting of atoms into compounds.
• B. The movement of electrons from cations to anions.
• C. The mutual attraction of opposite electrical charges.
• D. The sharing of electrons.

Chemical Bonds

Covalent bonding represents a type of chemical bonding. Here we have molecular bonds involving the sharing of valence electrons between nonmetals. Now if we take a look here, we have two chlorine atoms and two oxygen atoms. Chlorine is in Group 7A. It just needs one more electron to become just like argon, the noble gas next to it.

So how can it gain that one electron? What it does is it teams up with another chlorine or another element, and it's going to share one of the electrons from its neighbor. O here, the two chlorines, they're both going to share an electron with each other. So here are our chlorines and they're sharing 1 electron with each other. Neither one has sole possession of both electrons. They're sharing the electrons together. So in essence they both have reached the same number of electrons as argon. They're fulfilling, filling out their outer shell, and being like a noble gas.

Oxygen oxygen's in Group 6A, so it needs two more electrons to become just like neon. What does it do? It decides to share its two electrons with another oxygen. So here are our oxygens and sharing their electrons with one another. And in that way they've achieved in a filled outer shell, just like neon the noble gas closest to them. And notice here that these elements are forming the single bond between each other with the chlorines and a double bond between the oxygens.

As we delve deeper and deeper into different types of chemical compounds, we'll learn about the bonding preferences found between different elements. But remember, it's always trying to form the optimal number of electrons to help fill out their outer shell and become just like a noble gas, at least when we're talking about covalent bonding. So just remember, covalent bonding involves nonmetals sharing electrons with one another.

Chemical Bonds Example 2

Which of these elements is unlikely to form covalent bonds? So we have here sulfur, we have hydrogen, we have potassium, we have argon, and we have silicon. So remember covalent bonds are the sharing of electrons between non metals between nonmetals.

If we take a look here sulfur is a nonmetal so sulfur could form covalent bonds. Hydrogen is a nonmetal. Potassium is a metal. We said that it's between nonmetal, so this can't ever form covalent bonds. Let's look at the other options. We have argon and then we have silicon.

Argon is a nonmetal. Silicon is a metalloid. Now, technically, remember, metalloids share characteristics of both metals and nonmetals, and we'll see that because it's a metalloid and shares some nonmetal characteristics. There is the potential to form covalent bonds, right? So Eve has the potential.

C can't ever have the potential informing covalent bonds because it's strictly a metal. So just remember when it comes to covalent bonding, it's the sharing of electrons between elements that have non metallic characteristics.

Chemical Bonds

Metallic bonding represents another type of chemical bonding, but the name is a little bit deceiving. It's not really metals bonding together. What it is, it's the attractive force between free floating valence electrons and positively charged ions on a metal surface.

Now metallic bonding is important because it's responsible for the unique physical properties of metals, such as their malleability or their conductivity. If we take a look here at this image of metallic bonding, we have our positive ions on the surface of the metal and moving freely around. Are these negative electrons in green?

Now, these electrons are not confined to each of their metal or positively charged ions. They can actually move to the other ones. They're moving around freely. So metallic bonding is a little bit different from the chemical bonding we're custom to seeing.

Chemical Bonds Example 3

Which of the following is the best description of the free flowing electrons and metallic bonding? So here a core electrons that can move freely between metal ions. Remember we said it's valence electrons, the electrons that are found on the outer shell in terms of the element or ion. So this doesn't make sense. So A is out.

B would also be out because again it's including core electrons, valence electrons that can move freely between metal ions. That's what we showed in the picture. Those valence electrons are not confined to each one of their those positive ions, they can move around between them. So C is a good description.

D valence electrons that are bond to metal ions, they're not bound, they can freely move around. And then E again, core electrons are bond to the metal ions, yes, but metallic bonding has to do more with the free flowing of prevalence electrons between positive ions. So C is the best description of metallic bonding.

Which of the following is not a physical property attributed to metallic bonding?

• A. Ductility
• B. Luster
• C. Brittleness
• D. Malleability
• E. Conductivity

Which of the following statements is true?

• A. O₂ is characterized by metallic bonding.
• B. BaO is characterized by covalent bonding.
• C. H₂O is characterized by ionic bonding.
• D. Zn is characterized by metallic bonding.
• E. BeF₂ is characterized by metallic bonding.

Here’s what students ask on this topic:

What are chemical bonds?

Chemical bonds are the forces of attraction that hold atoms together in molecules and compounds. These bonds form when atoms share or transfer valence electrons, the outermost electrons that determine an atom's chemical properties. There are three primary types of chemical bonds:

1. Ionic Bonds: These occur when one atom donates an electron to another, resulting in the formation of ions. The positively charged ion (cation) and negatively charged ion (anion) are held together by electrostatic forces. Ionic bonds typically form between metals and nonmetals.
2. Covalent Bonds: Covalent bonds involve the sharing of electrons between atoms, usually between nonmetals. Depending on how the electrons are shared, covalent bonds can be classified as polar (unequal sharing of electrons) or nonpolar (equal sharing of electrons).
3. Metallic Bonds: Found in metals, these bonds involve a 'sea' of delocalized electrons surrounding positively charged metal ions. The electrons are free to move, which is why metals are good conductors of electricity.

The strength and type of chemical bond directly affect the properties of the resulting compound, including melting point, boiling point, conductivity, and reactivity. Understanding chemical bonds is fundamental to studying and manipulating chemical reactions and the properties of materials.

What are the three types of chemical bonds?

The three primary types of chemical bonds are ionic, covalent, and metallic bonds.

1. Ionic bonds occur when electrons are transferred from one atom to another, leading to the formation of ions. These ions are oppositely charged (cations are positively charged and anions are negatively charged) and attract each other, creating a bond. Ionic bonds are typically formed between metals and non-metals.
2. Covalent bonds are formed when two atoms share one or more pairs of electrons. This type of bond is common between non-metal atoms. The shared electrons allow each atom to achieve a stable electron configuration, similar to that of noble gases. Covalent bonds can be single, double, or triple, depending on how many electron pairs are shared.
3. Metallic bonds are found in metals, where atoms share a "sea" of electrons that are free to move around. This delocalization of electrons allows metals to conduct electricity and heat, and also gives them their malleability and ductility. In metallic bonds, the positively charged metal ions are held together by the surrounding cloud of electrons.

What is ionic bonding?

Ionic bonding is a type of chemical bond that forms between two atoms when one atom gives up one or more electrons to another atom. This process creates ions, where one atom becomes positively charged (cation) due to the loss of electrons, and the other becomes negatively charged (anion) due to the gain of electrons. The electrostatic attraction between the oppositely charged ions holds them together.

For example, in the formation of sodium chloride (table salt), a sodium atom (Na) donates an electron to a chlorine atom (Cl), resulting in a sodium cation (Na⁺) and a chloride anion (Cl^-). These ions are then attracted to each other to form the ionic compound NaCl.

Ionic bonds typically form between metals and nonmetals because metals tend to lose electrons easily while nonmetals tend to gain electrons. This bond is generally strong and results in the formation of ionic compounds, which are usually crystalline solids at room temperature and have high melting and boiling points.

What is covalent bonding?

Covalent bonding is a type of chemical bond where pairs of electrons are shared between atoms. This sharing allows each atom to attain the electron configuration of a noble gas, achieving a more stable state. In a covalent bond, the shared electrons belong to the outer shells of both atoms involved, and this sharing can involve one, two, or three pairs of electrons, leading to single, double, or triple bonds, respectively.

The strength of a covalent bond depends on the overlap between the atomic orbitals of the participating atoms. When atoms share electrons equally, it's called a nonpolar covalent bond. However, if one atom attracts the shared electrons more strongly than the other, the bond is considered polar covalent, leading to a slight charge separation within the molecule.

Covalent bonds are fundamental to the structure of many substances, particularly organic compounds, which make up all living organisms. These bonds determine the physical and chemical properties of molecules, such as boiling and melting points, reactivity, and electrical conductivity.

What is metallic bonding?

Metallic bonding is a type of chemical bonding that occurs between atoms of metallic elements. It involves the delocalization of valence electrons, meaning that the electrons are free to move throughout the structure. This sea of electrons surrounds a lattice of positive metal cations. The electrostatic attraction between these mobile electrons and the fixed cations is what holds the metal together.

This delocalization of electrons allows metals to conduct electricity and heat efficiently, as the electrons can flow freely through the metal. It also gives rise to other characteristic metallic properties such as ductility (the ability to be drawn into wires), malleability (the ability to be hammered into thin sheets), luster (shiny appearance), and opacity. The strength of metallic bonding varies among different metals and is a key factor in determining the melting point, hardness, and density of the metal.