Why? Because alcohols can be converted to almost every other aliphatic compounds!

What does the general formula look like?

Alcohols have the general formula ROH, where R is an alkyl or substituted alkyl group.

Let me explain this in an easier way.

We can say that when a hydrogen atom of an alkane is replaced by a -OH group, we get alcohol. Now after you take away one hydrogen atom from an alkane,  make a hydroxyl group take that empty position, dare you still call it by the same name? No, you have to get it a new name, the format of the name being (alka+nol).

This is how we get what are called the common names of alcohols.

For example, if you replace a hydrogen atom of propane by a -OH group, the alcohol you get would love to be called by the name propanol. Sounds sweet, doesn’t it?

Classification based on the position of the carbon bearing the -OH group

Now just like your schooling is divided into different stages such as primary, secondary and higher levels, alcohol, according to the kind of carbon that bears the hydroxyl group, is classified into three types – 1° or primary,  2° or secondary and 3° or tertiary.
Well, as you can see, all degrees certainly do not always represent temperatures.

The alcohol where the carbon atom adjacent to the hydroxyl group is bonded with only one other carbon atom is called 1° or primary alcohol. Similarly, the one where the carbon atom adjacent to the hydroxyl group is bonded with two other carbon atoms is 2° or secondary alcohol.

Now you should be able to define the 3° or tertiary carbon atom. Let me leave this task for you, please.

Propan-1-ol, propan-2-ol and 2-methylpropan-2-ol are examples of the three above kinds of respective systems. These are named according to the IUPAC system, one of the most versatile and the smartest systems ever introduced in the field of science.

For the simpler alcohols, the common names are used often. See! We human beings are not the only ones who have got gorgeous names, alcohols have got some too!

Classification based on structure: 

On the basis of the structure, alcohols are divided into two kinds- aliphatic alcohols and aromatic alcohols.
Again, Aliphatic alcohols may be saturated and unsaturated according to the nature of C-C bond.

Classification based on the number of hydroxyl groups present:

(a) Monohydroxy alcohol: One -OH group present.

(b) Dihydroxy alcohol : Two -OH groups present.

Ethylene glycol is a good example of dihydroxy alcohols.

1. c) Trihydroxy alcohol: Three -0H groups present. Glycerine is probably the most familiar example of this kind.

1. d) Polyhydroxy alcohol: Four -OH groups present. Sorbitol is a familiar example of polyhydroxy alcohols.

Physical Properties Of Alcohols

In alcohols, the carbon and the oxygen atoms are in sp3 hybridized state.
Out of the four hybrid orbitals of oxygen atom, two sp3 orbitals are completely filled.
These two completely filled sp3 orbitals do not take part in the bond formation.
The other two half-filled sp3 orbitals of oxygen atom take part in the sigma bond formation.
Thus C-O bond in alcohol is formed by the overlapping of one half-filled sp3 orbital of oxygen and one sp3 orbital of carbon atom of the alkyl group.
The bond between carbon atom of alkyl group and oxygen atom is thus sp3-sp3 sigma bond.
The other half filled sp3 orbital of oxygen forms a bond with orbital of hydrogen atom.
Thus O-H bond angle in alcohol is sp3

-s sigma bond. The C-O-H bond angle in alcohol is 105° which is less than the normal tetrahedral angle (109°28′).

This is because of the fact that the two unshared and completely filled sp3 orbitals of oxygen atom repel each other causing the reduction of C-O-H bond angle (VSEPR theory).

Common alcohols are liquids at room temperature. This must be a fact of no wonder to you as you have already watched a lot of movies where villains drink a lot of alcohol from glasses and you know what is drunk from glasses cannot but be liquids.

However, highly branched alcohols i.e. those with more than twelve carbon atoms are solid at room temperature.

Alcohols are colorless too. Oh! What a relief for those who are color blind!

Most of the common alcohols have got a fruit-like smell, making their presence quite easily detectable.

Let us look at the boiling points. Among hydrocarbons, the factors that are responsible for the determination of boiling points are mainly molecular weight and shape. Alcohols, as expected, show increase in boiling points with increasing carbon numbers and decrease in boiling points with branching. But what is unusual about alcohols is they boil so high, much higher than hydrocarbons with nearly similar molecular weights (Aristocracy, isn’t it?).

It is due to the greater energy required to break the hydrogen bonds that hold the molecules together.

The O-H bond in alcohols is highly polar which arises due to the high electronegativity difference between oxygen atom (3.5) and hydrogen atom (2.1). As a result, the oxygen atom of -OH group in alcohol carries a partial negative charge. Thus the polarity of -OH bond in alcohols gives rise to forces of attraction between partially negatively charged oxygen atom of one alcohol molecule and the partially positively charged hydrogen atom in another alcohol molecule. The force of attraction thus produced between hydrogen atom and another electronegative atom two molecules is known as hydrogen bond. Thus numerous hydrogen bonds are produced among the alcohol molecules. The alcohol molecules get associated with hydrogen bonding. Consequently, much higher energy is required to break these numerous H-bonding to bring the associated molecules in monomeric forms. As a result, the b.p. of alcohol becomes high. On the other hand, alkanes have no (-OH) group. So hydrogen bonds are not formed between the alkane molecules.

As a result, the b.p. of alkanes are low.

The fact that the lower alcohols are miscible with water also reflects their ability to form hydrogen bonds with water. The higher alcohols have bigger insoluble alkyl groups of comparatively higher mass. So the hydroxyl (-OH) group can not form hydrogen bonding with water molecules pulling the bigger alkyl group.

Therefore, alcohols of higher mass do not dissolve in water.

We better be like alcohols and with our close ones form a bond too strong to be broken easily!

The post Alcohols and their physical properties: A Proper Guideline appeared first on Chemniverse.

The Building Blocks: Atoms and the Periodic Table

Atoms are the basic units of all matter. Atoms consist of protons, neutrons, and electrons. The protons and neutrons reside in the center or nucleus of the atom, while electrons orbit around the nucleus. The number of protons in an atom determines its identity or element type on the periodic table of elements.

The periodic table orders the elements by increasing atomic number from left to right and top to bottom. It groups elements into broad categories of metals, nonmetals, and metalloids. The vertical columns or groups share certain qualities and reactivity trends.

The horizontal rows or periods indicate the number of electron shells. Common groups discussed in introductory chemistry include the alkali metals, alkaline earth metals, halogens, noble gases, and transition metals. Gaining familiarity with the groups and periods can help predict chemical behaviors of different elements.

Ionic and Covalent Bonds

Atoms form bonds or links with other atoms through the transfer or sharing of electrons. The electrons in the outermost shells are called valence electrons. An ionic bond results from the electrical attraction between positively and negatively charged atoms or ions after the transfer of valence electrons. Ionic compounds are typically formed between metals and nonmetals.

The atoms unite in ratios that produce neutral compounds. By contrast, covalent bonds involve the sharing of pairs of valence electrons between two atoms. The atoms in covalently bonded compounds usually have similar electronegativities or attractions for electrons. The bonded atoms attain a stable electron configuration similar to that of noble gases by sharing electrons. The degree of polarity in a covalent bond depends on how evenly the bonding electrons are shared between atoms. Polar and nonpolar covalent bonds manifest in different compound properties.

Chemical Reactions, Balancing Equations, Acids and Bases

Chemical reactions and equations demonstrate the rearrangement of atoms caused by breakage, formation, and reformation of chemical bonds. The reactions have definite quantities known as stoichiometry which serve to balance equations.

The reactants (starting materials) and products (resulting substances) are separated by an arrow. Coefficients are added before chemical formulas to satisfy the law of conservation of mass and balance the atoms. Acids and bases are important compound types that dissociate or ionize in water to release, respectively, excess hydrogen ions (H+) which lower pH and hydroxide ions (OH-) which raise pH.

Strong and weak acidity depends on the degree of dissociation and release of H+. Neutralization reactions between acids and bases result in salt and water formation. Understanding balancing equations and the behavior of acids/bases has many practical applications.

States of Matter

Matter exists as solids, liquids, gases and plasma. The states have notable distinctions. Solids have definite volumes and shapes from the close arrangement of particles. The more tightly bound particles vibrate in fixed positions but do not otherwise move freely. Liquids have definite volume but not shape.

Their particles move more freely past each other but are still closely packed. Gases have no defined volume nor shape as the particles move completely freely and are highly dispersed. Changes of state are explained by kinetic molecular theory. Adding or removing heat energy impacts the kinetic energy and motions of the particles.

Solids liquefy into liquids with added heat while liquids vaporize into gases with more addition of heat. The changes between states are indicated on heating and cooling curves. Understanding phase changes and associated energies is important across scientific disciplines.

Importance of Chemistry Concepts

Building knowledge in fundamental chemistry prepares you for more advanced study across the physical sciences and supports greater scientific awareness. Understanding atoms, elements, periodicity, bonding, reactions, acids/bases, and states of matter will help you better comprehend many important processes from materials properties to biological functions to the environmental phenomena you encounter everyday.

With foundational knowledge, you can move on to expanding your learning into subjects like nuclear chemistry, thermodynamics, organic chemistry, biochemistry, atmospheric chemistry and more while appreciating how these concepts tie together. Mastering chemistry basics equips you with scientific literacy to make informed decisions and allows you to fully appreciate the central, essential role chemistry plays in our world.

The post Basic Chemistry fundamentals-Your Guide to Core Concepts appeared first on Chemniverse.

When you hear the word metal, the picture that comes to mind is of something rigid, shiny, and cold object used in building large sturdy structures. Or do you think about the liquid metal cooling in the latest PS5? If not, then you might think of iron, copper, or steel. Yes, that’s the general picture of metals. But they are substances which can have three physical states. Have you ever thought of metals in their liquid form? If you did, it is probably in their hot molten, and glowing state.

But opposing that concept, certain few metals can also be found in their liquid state at normal temperature. Note that, in chemistry room temperature means 25 ˚C. But in general terms, it can have a wide range. So, metals that melt at a slightly higher temperature were also included.

The question comes to mind, why are they different? To know the answer, we have to know about metallic bonds, the bond between metal atoms. Here is a brief description. 

Metallic Bond

The characteristic of metals is just so that they neither completely give up nor hold in their outer shell electrons. As a result, their atoms create a matrix where they form positive ions and are surrounded by electrons. Think of a chunk of metal. In that chunk, there are numerous metal ions submerged in a sea of electrons which are loosely bonded to their atoms.

Those who have a slightly stronger attraction to electrons produce stronger metallic bonds and thus are solid at normal temperature. Most of the metals are this way. But a few have so little attraction that they produce very weak bonds and thus easily melt at normal temperature.

[If you want to know more details about the metallic bond, do not delay and check out our website]

Let’s stop talking about metallic bonds already and check out the very interesting stuff that liquid metal is.

Fireworks are one of the most beautiful things made by humans. But did you know that the colors of it are due to metal salts? One such metal is rubidium which is used to produce violet-red colored fire. And it is also one of the metals of today’s topic.

5. Rubidium (Rb)

Rubidium (Rb) is an alkali metal of the 5^th period with an atomic number of 37. It is just below the potassium in the periodic table. It has a melting point of 39.3 ˚C (102.74 ˚F), a bit above our body temperature. It is not found readily in its liquid form but if you consider countries with a very hot climate you may find it in the liquid state under normal condition. Thus, rubidium was able to make a place for itself in the list of metals that are liquid at room temperature.

When not in liquid form it is so soft that you can easily cut it with a kitchen knife. It has a common silvery-white appearance. The name rubidium originates from the Latin word rubidius, which means deep red. You might be thinking, how in the world red and rubidium is related. It is because the atomic spectrum of rubidium has unique red lines. Although rubidium is not that well known and does not have that much use, it still has few very important uses. 

The color of the flame of rubidium chloride (RbCl) is violet-red and so it is used in fireworks to produce beautiful violet colors. Fireworks are short-lived. But the isotope rubidium-87 has a half-life of 49 billion years which is 3 times the age of the universe. You may forget the sense of time while looking at beautiful fireworks. So, you would want to look at your clock to check the time. While you are happy if your clock is accurate to minutes, scientists need clocks that are more sensitive and accurate. And the isotope rubidium-87 does just that. It is used in atomic clocks due to its extremely high accuracy. Rubidium is also used in treating depression.

Even though rubidium sounds so good you must be careful around it. It is the second most electropositive metal on earth. It is so reactive that it will self-ignite in open air by reacting with atmospheric oxygen. It also reacts explosively with water. For this reason, rubidium is stored in an inert atmosphere or submerged in dry oil e.g., kerosene.

Enough with rubidium. Let’s check out our next liquid metal.

4. Gallium (Ga) 

Gallium (Ga) has a melting point of 29.76 °C (85.57 °F). Although like rubidium it also has a melting point above room temperature, it is not that high. And it even melts in your hand. So, gallium’s position in this list is well deserved.

The phrase “melts in the mouth” is just perfect for this element. Wait, don’t try it. Gallium is not toxic in a small amount. But there is little knowledge. Guess, it doesn’t taste that good then. Still don’t try it.

Gallium sits just below aluminum in the periodic table with an atomic no of 31. And has a silvery-white appearance. Its discoverer, Paul-Emile Lecoq de Boisbaudran named it after the Latin word ‘gallus’ meaning ‘Gaul’ which is the old name of France, his homeland. Although some believed he named it after himself as both gallus and Lecoq mean rooster, this idea was denied. 

Like aluminum, it has also proven its importance through many uses. When someone gets a fever, what you do first is to measure the temperature using a thermometer. What has gallium got to do here? You have guessed it correctly. Gallium is used in thermometers instead of mercury. Mercury is toxic whereas gallium can melt in the mouth. I would definitely choose gallium over mercury.

There are many other substances that can be used in thermometers. But gallium can do much more. At this age, there is no way you have not heard about semiconductors. Yes, gallium is one of the very few elements that is used to produce semiconductors. If you have a computer, you probably know what a solid-state drive is. The successor of hard-disk drives which are many times faster and more durable while much smaller. Don’t be surprised. Gallium semiconductor is used to make those fast storage devices. 

Not everyone likes techs and things like these. But they sure do like to watch a good magic trick. Or even better, do a magic trick and get everyone’s praises. And gallium can help you do just that. Want to know how? A magician never reveals his secret. But hey I am no magician. The trick is called the vanishing spoon trick. For this, you need a spoon made of gallium metal. Act as if you are making tea for your friends and now stirring the warm tea with a ‘spoon’. Voila, the submerged part of the spoon is gone. Isn’t it fun to look at friends’ stupefied faces? 

Is that you, T-1000?

Not only this, gallium is used in a fun experiment called beating heart where it literally beats like a living thing. Science sure is fun and interesting and of course amazing. Won’t you agree?

Ah, there is one more important use of gallium which is to make alloys, solid solutions. As gallium is liquid it can easily dissolve a lot of other metals. Try putting gallium on a soda can. Be sure to remove any paint coatings. And see the magic.

There are many more fun and important uses of gallium but others are waiting in line.

So, let’s hurry and move on to our next metal on the list.

3. Cesium (Cs)

(IUPAC name – Caesium)

Our next metal in the list, the one that has been hailed as the most electropositive element on earth, is none other than cesium (Cs). It has a melting point of 28.5 °C (83.3 °F), which is almost equal to that of gallium. But don’t ever try taking it even in your hands. You will know why in a bit. It has atomic no 55 and has the 2^nd lowest position in group-I which is just below rubidium. As a metal from the same group, it has lots of similarities with rubidium. They are just like brothers. The name cesium comes from the Latin ‘coesius’ which means sky-blue. Like rubidium, cesium got its name from the color of atomic spectral lines which are blue. But unlike other group-I metals, it has a pale gold appearance.

As you have read earlier, cesium and rubidium are like brothers but cesium is like the older one. More ductile, more reactive, more electropositive, and thus more hazardous. The explosions it creates while reacting with water is so violent that it can even break the vessel if it is made of glass.

And yeah, cesium too is used in atomic clocks, specifically, the cesium-133 isotope is used. But it is more accurate. In fact, it is the most accurate measurement humans have ever achieved. This fact is a lot more than it sounds. It has so little error that it would take 20 million years for a cesium clock to deviate by just 1 second. How cool is that!!

Not just that. The very unit “a second” is defined in terms of cesium! The time it takes for cesium to complete 9 192 631 770 ground-state transitions is equal to one second. Imagine, for every second that passes, a cesium atom vibrates 9 192 631 770 times.

Cesium has four isotopes among which only cesium-133 is stable while others are radioactive. And the use of cesium mostly involves its radioactivity.

You saw that the melting point decreases as we go down the group-I metals. And cesium is the 2^nd lowest metal. So, shouldn’t the lowest metal have an even lower melting point? And yes, our next metal is francium, the last member of group-I.

2. Francium (Fr)

Francium was discovered in France by Marguerite Perey in 1939 and was named after the country. It is situated in group-I, period-7 In the periodic table. Just below cesium.

It is the second rarest naturally occurring element on earth. It is radioactive and has a very short half-life. Even the most stable isotope francium-223 has a half-life of only 22 minutes. It is naturally produced through the decay of actinium but itself decays into astatine, radium, and radon. It is found in trace amounts with uranium ores. Believe it or not, you can find only about an ounce (20-30 grams) of francium in the earth’s crust at any given time but that would also decay. And only a few hundred thousand atoms were synthesized by humans. You would have to pay billions of dollars only to get a few grams of this substance. And so, not much about francium is known. 

It has a melting point that is uncertain and estimated to be 8.0 °C (46.4 °F). You may think that francium should have been the most electropositive metal instead of cesium. But it has been predicted that its radioactivity might interfere which on contrary will lower the electropositive nature.

 Being so rare, it has no commercial applications. It has been used in scientific research only.  Scientists also tried to apply it in cancer diagnosis but it was found to be impractical.

We might not know a lot about francium. But our next and last metal has been familiar to humans since a long time ago. And it is none other than mercury.

1. Mercury (Hg)

Mercury is the top liquid metal on earth. It is the only metal that is liquid at standard temperature and pressure (0 ˚C, 1 atm). It has a melting point of −38.82 °C (​−37.89 °F) which, as you can see, is way lower than even water. 

It is a transition metal with an atomic number 80 and an atomic mass of 200.592. It has a shiny silvery appearance and so it is also called quicksilver. It is named after planet mercury due to its high speed. The Latin name of mercury, hydrargyrum, comes from the Greek word hydrargyros which literally means water-silver.

Although mercury is not very reactive and does not react with most acids, it is very toxic for humans and other animals. It accumulates in the body and causes various diseases and mercury poisoning. But It has a lot of uses in our daily life.

Mercury was familiar to humans since as early as 1500 BCE. And still is heavily used. It might surprise you, but it is a rare metal. The major source of mercury is cinnabar, an ore of sulfur (HgS) which is also called red mercury because of its color.

When you hear mercury, you probably think of a thermometer. As you already know mercury is liquid under normal conditions. And luckily, its volume changes uniformly with temperature which makes it a suitable material for thermometers. But it has a lot of other uses. The ancient people produced red pigment called vermillion using cinnabar. And It was of great importance in alchemy. Although it might shock you, mercury was therapeutically used until as late as the 18^th century. More shocking, people believed that drinking mercury prolongs life which on the contrary caused them an early death. Ironic, isn’t it?

Although in decline, mercury is used a lot. The first thing that comes to mind after the thermometer is the air pressure. Atmospheric pressure is also expressed in mmHg units ( 1atm=760mmHg). And thus, mercury is used in the barometer, the device used to measure the pressure of atmospheric pressure. It is used in making fluorescent light also known as neon signs. The major use of mercury is in the PVC industries of China. And it is China that is the major supplier of mercury. You have already read about atomic clocks. The fact that they are super accurate is amazing but the downside is their large size. Accuracy of time is very important in space for astronauts and other spacecraft. Luckily NASA has developed an ultra-precise miniaturized atomic clock using mercury which albeit not as accurate as of the cesium clock, is much smaller. 

You might have already guessed that liquid metal mercury must have contributed to producing alloys (metal solutions). You are right. Mercury forms amalgams, Meaning alloys of mercury, with almost all metals except iron. You can even extract gold using mercury as a solvent. An interesting fact is that mercury is not allowed to carry on planes because of how easily it forms an amalgam with aluminum, the major component of a plane’s structure. Did you already know that? Well, now you know. If you know someone who likes sweets and candies too much and unfortunately caused cavities, you might know dentists use a type of paste as filling. Don’t be surprised, mercury is used to make that paste. 

All the known forms of mercury are harmful and toxic. We now end this list wishing you to be safe from harmful chemicals.

But before going let’s know a bit more about liquid metal in general. Although the existence of liquid metal has been known to humans for a long time, this property has been mostly used for producing alloys and nothing much. But now more work is being done on this property. You might have already understood that common properties of metal such as conducting heat or electricity would not be the same for the liquid state. The liquid metal processor coolers for high-end computers or the latest model of PlayStation, PS5 are just the beginning.

With the desire to serve more interesting and amazing content, Goodbye!!

The post The Only 5 Metal Elements on the Periodic Table which are Liquid at Room Temperature appeared first on Chemniverse.

The Main Parts of an Atom

Atoms contain three primary particles: protons, neutrons, and electrons. The protons and neutrons exist in the core or nucleus of the atom. The electrons orbit around this nucleus in shells.

Protons – These are positively charged particles in the nucleus. The number of protons defines what element the atom is. For example, all carbon atoms contain 6 protons.

Neutrons – Neutrons have a neutral charge. They are also found in the nucleus and contribute to the atom’s mass.

Electrons – Negatively charged electrons orbit outside the nucleus. Atoms want to have a neutral charge, so they contain equal protons and electrons.

The number of protons and neutrons determines the atom’s atomic mass number. Isotopes are variations of an element with the same proton number but different neutron numbers.

Atomic Structure and Subatomic Particles

The smallest unit of an element that still retains the properties of that element is an atom. Atoms are extremely small, around 0.1 nanometers in diameter. But they contain three distinct subatomic particles:

Protons – Positively charged particles found within the nucleus of an atom. The number of protons defines an element’s atomic number.

Neutrons – Electrically neutral particles found within the nucleus. Neutrons help stabilize the nucleus.

Electrons – Negatively charged particles that orbit the nucleus. The number of electrons is equal to the number of protons in an electrically stable atom.

These fundamental particles interact to form the basic atomic structure that makes up all matter. The properties of different elements come from the unique number of protons, neutrons, and electrons within their atoms.

What are Isotopes?

Isotopes are variations of the same element with different numbers of neutrons. Isotopes of an element have atoms with the same number of protons but differing numbers of neutrons. Because they have the same number of protons and electrons, isotopes exhibit the same chemical behaviors. But differences in neutrinos change their mass and some physical properties.

Some elements, like carbon, hydrogen, and oxygen, have naturally occurring stable isotopes. Other isotopes may be unstable or radioactive, like uranium-235. The various isotopes of an element are denoted by their mass number. This is the sum of the number of protons and neutrons in the nucleus.

For example, the three main isotopes of carbon are:

Carbon-12: 6 protons + 6 neutrons = mass number 12

Carbon-13: 6 protons + 7 neutrons = mass number 13

Carbon-14: 6 protons + 8 neutrons = mass number 14

Although they have different mass numbers, they are all carbon atoms because they contain 6 protons. The chemical properties remain unchanged between isotopes. But isotopes have slightly different physical properties like atomic mass and radioactivity stability.

Isotopic Notation

Isotopes are identified by their atomic mass number and represented in isotopic notation. This notation puts the mass number after the element’s name or symbol.

For example:

– Carbon-14 = 14C
– Uranium-235 = 235U
– Hydrogen-2 = 2H

The atomic mass number is superscripted before the element’s symbol. This notation specifies the isotope’s mass number (protons + neutrons) uniquely from just writing the element. It also distinguishes between an element’s different isotopes.

Isotopic notation allows us to represent the specific isotope rather than just the element generally. This is extremely useful across chemistry, physics, geology and a number of other scientific areas that utilize isotope analysis.

Key Applications of Isotopes

– Radiometric dating – Radioactive isotopes like carbon-14 can be used to accurately date ancient fossil, rocks, and artifacts. As radioactive isotopes decay at known rates, measuring isotope concentrations reveals time passed.

– Medical tracers – Safe radioactive isotopes like technetium-99 can track internal organ function and abnormal tissue in PET scans and similar diagnostic tests.

– Stable isotope analysis – Variations in stable isotope rations of carbon, nitrogen, oxygen and more can detect adulterated food products, study ancient diets, and trace pollutants.

– Food and health safety – Regulatory testing looks for radioactive isotopes from contaminants and toxins to ensure food and products are safe for human consumption and use.

Atomic structure defines the basic components and interactions that build up all the physical world around us. Understanding principles of atomic particles, elements, isotopes and radioactive decay is fundamental to the wider field chemistry and its many applications across science and industry. A solid grasp of these atomic properties and processes forms the foundation for delving deeper into the exciting world of chemistry.

The post Atomic Structure And Isotopes And Isotopic Notation appeared first on Chemniverse.