Atoms are the building blocks of matter. Everything we see around is composed of millions and billions of atoms. Have you ever wondered how these atoms are held together?
The atoms are held together by chemical bonds. The formation of chemical bonds is an intrinsic property of atoms; they form bonds to make them stable. Mainly, there are two types of chemical bonds i.e. covalent bonds and ionic bonds.
In a covalent bond, the two atoms forming a chemical bond share an electron. A covalent bond may be single, double, or triple based on how many electrons are shared. The compounds formed as a result of covalent bonding are called covalent compounds. Water (H2O), Carbon-dioxide (CO2), and Oxygen (O2) are a few covalent compounds.
In the case of an ionic bond, the transfer of an electron takes place from one atom to another atom. The atom which donates an electron becomes positively charged and is called a cation, while the atom which receives an electron is called an anion. This bond is between two ions, that’s where it gets the name ionic. Some examples of ionic compounds include table salt (NaCl), Sodium Hydroxide (NaOH), etc.
Since chemical bonding is the basis of chemistry, you will have to teach this topic during the introductory chemistry course. Students may find this topic hard to understand. So, read on to learn five strategies through which you energize students about Ionic and Covalent Bonds.
Chemistry is considered one of the tough subjects, the same is the case here. Here are three reasons the concept of ionic and covalent is hard for students.
Chemical Bonding feels like an abstract concept. The sub-atomic particles called electrons, within the microscopic atoms, participate in chemical bonding. It is impossible to visually imagine this type of reaction. And without any attractive visuals, the subject matter seems hard and dry for students.
When distinguishing between the type of chemical bonds, the concept of electronegativity is quite important. The electronegative difference between two bonding elements tells us about the nature of the bond that will be formed between them. So, students may need to remember the electronegativity values of some elements.
When writing the detailed chemical bonding kinetics, students have to draw the valence shells of atoms of each element taking part in the chemical. For that, they need to know the electronic configuration of elements. Again, remembering these values and then drawing the Lewis structure can be hard for students.
Keeping in view some of the reasons why the topic is tough for students, here are five suggestions through which you can make ionic and covalent bonds an easy-to-understand topic for students.
Sometimes, students lack a proper understanding of the internal structure of atoms. Moving ahead without teaching basics may not be a good idea.
Start with basics; tell them about the internal structure of an atom, and how the electrons, protons, and neutrons are arranged. You can tell them that the center of an atom is called the nucleus. It contains positively charged protons and neutrons. Around the nucleus, electrons revolve in different shells. These electrons of an element take part in chemical bonding.
The next thing to mention is valency. It is a property that tells us about the combined capacity of an atom with other atoms. Valency is governed by the presence of electrons in the outermost shell (valence shell). As a general rule of thumb, an atom needs to have 2 or 8 electrons in its valence shell to become stable.
For instance, if an atom has one electron in its outermost shell, it can either donate that electron or take an electron to fulfill its duplet. Another example can be carbon, it has four electrons in the outermost, meaning it will need four electrons to fill its valence. In this case, the valency of carbon is four.
Figure: The Atomic Structure of Potassium and Chlorine from Labster’s Simulation on Ionic Bonds.
Another important property, that you must mention is electronegativity. It is the ability of an atom to attract shared pair of electrons. There are two types of bonds, ionic and covalent; one involves sharing and the other involves complete transfer of an electron, the electronegativity difference between the two atoms forming a chemical bond is quite important. As the difference increases, the bond polarity shifts from covalent to ionic. An electronegativity difference greater than 1.7 makes a chemical compound ionic.
Lewis structure is the key to describing chemical bonds among atoms in a molecule. It is a concise way of representing the valence electrons of an atom and helps to predict the nature of the reaction that the atoms may undergo. Students often have difficulty understanding the Lewis structure. The best way is to explain it in simple steps.
Here’s a step-wise procedure you can adopt when drawing the Lewis structure of an atom or group of atoms in a compound.
Locate the position of the element in the periodic table i.e. find out the group where it’s located. Count the groups from left to right, skipping transition elements. The group number mentions the valence electrons (except in Helium). For instance, the top element is Group I hydrogen has 1 one electron in its valence shell.
Write the symbol of an element, and place one dot for each valence electron. If the valence electrons are more than 4, such as in nitrogen (5) and oxygen (6), the electrons are written in the form of pairs, called lone pairs.
Figure: Lewis Structures of some common elements
For writing a structural formula of a molecular compound, you will need to find the valence electrons of each atom involved.
Then, find the number of electrons required to fulfill the octet.
Figure out the central atom of the compound, and write element symbols.
Place dots around the symbols, and then connect the dots where the atoms form a single bond.
For teaching chemistry to kids, multiple analogies can be used. The technical terms may be hard for them to digest. However, if you explain the same concept with some real-life analogies, that makes it easier for them to comprehend.
For instance, consider two siblings, John and Michael. John has 9 toys and Michael has 7 toys. Now, their parents want to divide the toys equally among them. So, they ask John to give one toy to Michael. In this way, both now have 8 toys each. The same happens in an ionic bond, if one atom has let’s say 9 electrons in its valence shell, it transfers one of its electrons to an atom with 7 electrons. As a result, both the atoms complete their octet and form an ionic bond.
To explain a covalent bond, you can use another analogy. Consider you have 3 burgers and you want to divide them among two people. You can give each person a burger a then share the third one by giving half to each person. The same kind of sharing takes place in the case of covalent bonds. An electron, instead of being completely transferred, is shared among the two atoms forming the bonding.
Chemical bonding, just like other chemistry topics, is rough and dry. To make it more appealing, you can share some interesting facts about ionic and covalent compounds.
An ionic bond is formed usually between metals and non-metals. For instance, Sodium (Na) forms an ionic bond with Chlorine to form Sodium chloride.
The covalent bond is usually formed between non-metal and non-metals. For instance, in water (H2O), the hydrogen and carbon atoms share a covalent bond.
Another important fact is that no bond is 100% ionic in nature. 100% ionic means a complete transfer of electrons from one atom to another atom, and that never takes place. So, when we say the bond in NaCl is ionic in nature, it means the more prevalent character is ionic. To be more precise, NaCl is 75% ionic and 25% covalent.
On the other hand, a covalent bond can be 100% covalent if atoms forming a chemical bond are identical.
In general, ionic bonds are stronger compared to covalent bonds. That is why, the ionic compound exists as solids, while covalent compounds are in a liquid or gaseous state at room temperature.
With technological advances, it is much easier to explain complex and tough processes with the help of simulations. Now, you can simulate experiments without the need for any practical equipment.
In this regard, you can take help from Labster’s virtual lab simulations. These simulations engage students through interactive learning scenarios. Students dive into a 3D world, where they visually learn and apply their concepts to solving real-life problems.
In Labster’s interactive simulation of ionic and covalent bonds, students first learn the basics of chemical bonding and apply their concepts to find found out about the nature and physical properties of two unknown substances.
If you are interested in buying our simulation package for your students, you can contact us now. Feel free to ask any questions!
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