The difference between ionic and covalent bonds isn’t as complex as you’d think. Image by Decoded Science
Almost all the atoms found in nature, left alone to themselves, are stable structures. If they always remained such, there would be no need of chemists.
Fortunately, when in close contact, atoms can react in a number of ways.
Often they link to each other in various combinations through bonding, forming molecules called compounds.
Such interaction requires explanation, and so provides employment to humans educated in this field: The field called chemistry.
Chemical Bonds: Ionic and Covalent
There are a variety of ways atoms bond to one another. Some bonds are weaker, and some are stronger. Two of the strongest forms of chemical bond are the ionic and the covalent bonds. Chemical bonds form between two atoms, each with its own electron environment.
- If each of the two atoms shares an electron with the other atom nearly equally, the bond is called covalent.
- If one atom exerts considerable force over the other atom’s electron, while the other atom strives to give its electron over, the bond is largely ionic.
Which form of bond—covalent or ionic—is the stronger? The easy way to determine that is to measure the energy it takes to break the bond. That quantity is called bond dissociation energy. The greater the energy it takes to break the bond, the stronger that bond must be. It turns out that most ionic bonds are considerably more difficult to break than covalent bonds.
Ionic Bonds: Electronegativity
In the 1930s, Dr. Linus Pauling expounded on the quality he called electronegativity. Some atoms, if they can be humanized, desire to increase their electron density. Others desire the exact opposite. He developed a list of numbers that quantified that affinity. The presence of appreciable electronegativity favors ionic bond formation.
The simplest way to determine which of the ionic bonds are strongest is to examine the electronegativities of the anion (the negative portion of a compound) and its cation (the positive portion of the compound).
Alkali Metals and Halogens
The alkali metals are the least electronegative elements found in the periodic table, whereas the halogens are the most electronegative elements. We list three combinations of these elements, lithium iodide, potassium chloride and rubidium fluoride.
Lithium iodide———-352 kilojoules per mole
Potassium chloride—-427 kilojoules per mole
Rubidium fluoride—-494 kilojoules per mole
Stronger than even these should be the ionic bond in the compound francium fluoride. It is the most electropositive of the elements. Hence, it follows that francium is the least electronegative element, as well.
Chemical Bonds and Electronegativity
In chemistry, we study the interactions between atoms. Elements stick together via chemical bonds; covalent and ionic, including Linus Pauling’s electronegative elements. Which bonds are the strongest? It depends on their properties.
Resources
University of Buenos Aires. Properties of Atoms, Radicals, and Bonds. Accessed October 15, 2013.
Linus Pauling. The Nature of the Chemical Bond. Electronegativity: Narrative. Oregon State University. Accessed October 15, 2013.
Well explained.
Which bond is more stable ionic or covalent and why??
I came to know that covalent is more stable than ionic bond but howw
Plzzz explain..
Vincent Summers says
Smriti… I can best illustrate what I believe you are thinking of using two compounds, methyl “cyanide” [CH3CN] and sodium cyanide [NaCN]. The first is covalent, the second, ionic. Covalent methyl cyanide does not ionize in water. That is, you do not get CH3 and CN ions by dissolving in water. NaCN, however, produces ions. That is, it breaks into two pieces, each piece of which is surrounded by water molecules. However, and this is the point, although it is less stable with regard to coming apart in water, that is only temporary. When the water evaporates, you still have NaCN. So this dissolution in a solvent does not mean the ionic bond is weaker. It is simply less stable as a single entity in an appropriate solvent such as water.
Just trying to clarify for myself: The alkali metals are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). These are LEAST electronegative, therefore the most electropositive? Electropositivity increases as you go further up the periodic table?
Halogens fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These are the most electronegative with the greatest electronegativity being in those at the TOP of the periodic table?
So the greatest strength ionic bond is where the most electropositive (Fr) is matched with the most electronegative (F)? This would be FrF? Does this exist?
Vincent Summers says
You’ve got it. However, cesium is more electropositive than francium ‘because of relativistic effects’.
Wow. That’s a lot of cool facts.
Ionic bonds r stronger than covalent and it is well known fact but in reality diamond which has covalent bonding is hardest substance…and why is it so?i mean the hardest substance in universe should be ionic not covalent
Vincent Summers says
Diamond is not the hardest substance known. And, even if it were… why should this depend upon being ionic or covalent?
Diamond does turn to graphite eventually overtime
You are correct but the covalent bond is also present in the graphite why they are not hard because the covalent bond is depend on the bonding between the atom and the high melting point not on there physical behaviour.
On the other hand ionic bond is strong because the forces of attraction between the ion of opposite charge and repulsion between the ion of same charge.
This is exactly the beauty of chemistry. The most important thing to consider in regards of a material strength is not its bonding type nor the elements, but rather on how those components are arrange to one another. Both diamond and graphite consisted of purely carbon atom, but on diamond those carbon atom bonded in a Three Dimension Vector, does making it have a very high bonding energy, thus difficult to break. While graphite only bond to the carbon existing on the same plane as your reference thus making it very brittle and easy to break.
Yes diamond is the hardest substance known…
Its covalent bonds are arranged in tetrahedral manner which makes it one of the most stable compounds.
Both ionic and covalent bonds are strong but unlike ionic structures, covalent once have weak intermolecular bonding and therefore they can break easily. When covalent bond form giant covalent lattices like in diamonds covalent bonds exist throughout the structure and it takes way more energy to break them and this makes them harder and an anomaly in the covalent structure. Hope it helps
Diamond is hardest substance because it has large number of tetrahedral covalent bonds which bonds make it very Strong and due to large number of covalent bonds it has very High boiling point………….
Vincent Summers says
How did this conversation start? I never wrote about sexuality. Something strange is going on here.
This has everything similar to the attraction between humans…think about it..we and everything in the multiverse is essentially energy constantly changing form. The pattern remain silent the same on a large scale or a quantum scale.
Dr. B Wynn says
The strength of Ionic and covalent bonds is similar the love between humans, where ionic represents woman and man (one has the electron the other needs), and covalent represent two people of the same sex (sharing electrons).
There’s possibility for two people of the same sex to possess a stronger love for one another than a man and woman, However, the strongest love possible for any one person, man or woman, is from that of the opposite sex; for from that bond, love can be made naturally in ways foreign to one of the same sex.
Vincent Summers says
An interesting allusion, illustration. Understandable to the reader.
Maybe the ionic bond metaphor is correct but not as you said. Only because one atom is much more dominant in the relationship and they are not equal
Are the electrons a euphemism for the male genitalia?
What an alienating thing to say. Why slander homosexuals to make a point about chemistry?
Nice explanation sir
But the metallic bond is stronger than the ionic and covalent bond.
How to explain it sir ?
Vincent Summers says
Phosphates used in fertilizers contain no heavy metals.
Nice Answer ..i love the way you explain
Vincent Summers says
That’s kind of you. I appreciate it.
Speed of the chemical reaction is affected by the type of the bond
When it is ionic it will be faster is that true?
Vincent Summers says
That’s a safe assumption.
Right
Ya its true
Nice web.
I don’t belongs to chemistry but interested in it.
If any body knows than plZ tell me.
Which elements or chemicals can pull carbohydrates (rice) from one point to other.
Vincent Summers says
Let the reader use discernment: some of the comments above are not valid arguments.
Yeah….this is absolutely right.
Covalent bonds an ionic bonds are fairly equal in terms of strength, the reason covalent bonds are “weaker” (mp/bp) is actually due to most covalent compounds being simple molecular compounds. This means they are comprised of a maybe a dozen atoms or so…the molecule itself won’t decompose but it will melt due to intermolecular forces being weak, ionic compounds are all bonded together and every ion is bonded to 6 ions around it, meaning they have higher melting points. If you think about it giant covalent structures like diamond and silicon dioxide have very high melting points because even though they are covalent, every atom is bonded to the ones around it. So they aren’t weaker.
what? It has to do with atomic mass. Electrons will automatically try to ionize (neutralize) with other atomic electrons in order to stabilize or (ionize). Think magnets vs. plastics.
Ionized particles are great conductors for this reason – stable..
When the strength of ionic bond increases, its ionic nature decreases and covalent nature increases. But why covalent bonds are less stronger?
“The greater the energy it takes to break the bond, the stronger that bond must be. It turns out that most ionic bonds are considerably more difficult to break than covalent bonds.”
That doesn’t really make sense. Covalent bonds are stronger than ionic and covalent bonds should have higher energy.
Vincent Summers says
Some do say covalent bonds are stronger; it is plausibly arguable both ways.
Ya thats true…
Think of it as if it is a magnet. Ionic bonds are between a metal and a non-metal. Metals generally need to lose electrons while non-metals need to gain them. this makes metals and non-metals attract, kinda like a magnet. The atoms exchange electrons and become ions, the metal has a positive charge because it has more protons than electrons, and the non-metal gains an electron and now the electrons are more numerous than the protons. The atoms then pretty much act like a magnet because one is positive and one is negative, so the stick together because opposites attract.
covalent bonds are shared electrons between two non-metals, they share the electron(s) to become stable, but both are negatively charged atoms, so the attraction is less. you don’t have the same magnetic styled attraction. I hope this kinda made things a bit clearer.