Things are made of tiny bits.
Sometimes, two different kinds of bits join together. They stick to make something new. This can be water. It helps us live. Can you find something new today?
Tiny bits make up everything.
Some bits are the same. But a compound uses different kinds of bits. These bits stick together to make something new.
One example is water. Water has two bits of one kind. It also has one bit of another kind.
These bits stay in a set pattern.
Sometimes, these bits can change. They can break apart. Then they join with new bits. This is called a reaction. It makes a new thing.
There are many kinds of these things. Some are hard and break easily. Others can be metals. There are over 350,000 kinds known today. It is a big world of tiny bits!
A chemical compound is a special substance. It is made of two or more different types of atoms. These atoms are called elements. The atoms stay together in a fixed way.
Atoms stay together using chemical bonds. These bonds act like glue. There are four main types of bonds. Molecular compounds use covalent bonds. These happen when atoms share electrons. Ionic compounds use ionic bonds. This happens when one atom gives an electron to another. Intermetallic compounds use metallic bonds. There are also coordination complexes with coordinate covalent bonds.
We can use a chemical formula to show what is inside. A formula uses symbols and small numbers. For example, water is H2O. This means it has two hydrogen atoms and one oxygen atom.
Compounds can change into new things. This happens during a chemical reaction. In a reaction, old bonds break. Then, new bonds form to make a new substance. There are more than 350,000 known compounds in the world today.
A chemical compound is a special kind of substance. It is made of two or more different types of atoms. These atoms are called chemical elements. The atoms stay together in a fixed way using chemical bonds. A bond acts like a connection between atoms. If a molecule only has one type of element, it is not a compound.
There are four main ways these atoms bond together. Molecular compounds use covalent bonds, which happen when atoms share electrons. Ionic compounds use ionic bonds, where one atom gives an electron to another. This creates positive and negative charges that pull them together. Intermetallic compounds use metallic bonds between metal elements. Finally, coordination complexes use coordinate covalent bonds.
People have studied these substances for a long time. Robert Boyle wrote a famous book in 1661. It was called "The Sceptical Chymist." He used words like "compounded body" to describe them. He also talked about tiny pieces called corpuscles. Later, Isaac Watts gave a very clear definition in 1724. He helped people see the difference between an element and a compound.
Scientists use special tools to identify and name compounds. A chemical formula shows the exact number of atoms in a substance. For example, water is H2O. This formula means it has two hydrogen atoms and one oxygen atom. Many compounds even have a unique CAS number. This is a special ID number from the Chemical Abstracts Service. Today, there are more than 350,000 registered compounds.
Compounds can change into new things through a chemical reaction. During this process, the old bonds between atoms break apart. Then, new bonds form to create a different substance. This is how one thing becomes something else. You can see this in many parts of our world. For instance, some compounds make up the Earth's crust and mantle.
A chemical compound is a substance made of two or more different types of atoms. These atoms are called chemical elements. In a compound, these elements are held together in a fixed, specific proportion. This means the ratio of one element to another stays the same. For example, water is always made of two hydrogen atoms and one oxygen atom. We write this as H2O. If a group of atoms only contains one type of element, it is not a compound.
Chemical compounds are held together by chemical bonds. These bonds are the forces that connect atoms in a specific spatial arrangement. One common type is the covalent bond, also called a molecular bond. This happens when atoms share electrons to reach a stable state. Another type is the ionic bond. This occurs when one atom transfers electrons to another atom. This transfer creates oppositely charged ions. The positive ions are called cations, and the negative ions are called anions. These opposite charges pull the atoms together through electrostatic forces.
Scientists classify compounds into four major types based on their bonding. Molecular compounds use covalent bonds to hold atoms together. Ionic compounds, often called salts, use ionic bonds. These often form continuous three-dimensional networks rather than individual molecules. Intermetallic compounds are a type of metallic alloy. They form an ordered solid-state structure between two or more metallic elements. Finally, coordination complexes use coordinate covalent bonds. These consist of a central metal atom or ion, called a coordination centre. This centre is surrounded by molecules or ions known as ligands.
The study of these substances has a long history. In 1661, Robert Boyle published a book called "The Sceptical Chymist." He used terms like "compounded body" and "perfectly mixt body." Boyle also used the idea of "corpuscles" or "atomes" to explain how elements combine. Later, in 1724, the English minister Isaac Watts provided a clearer definition. He helped distinguish between a chemical element and a chemical compound using modern terms.
Chemical reactions allow compounds to transform into new substances. During a reaction, a compound interacts with another substance. This process involves breaking existing chemical bonds between atoms. Once the old bonds are broken, new bonds form between different atoms. This creates a completely different chemical composition. This mechanism allows for the vast variety of materials found in our universe.
There are many ways to identify and measure compounds. Scientists use a chemical formula to show the number of atoms in a molecule. They use standard chemical symbols and numerical subscripts to do this. Many compounds also have a unique CAS number. This identifier is assigned by the Chemical Abstracts Service. Today, more than 350,000 chemical compounds and mixtures are registered for use globally.
Some substances are more complex than simple compounds. Non-stoichiometric compounds are a disputed or marginal case. In these substances, the proportions of elements are not simple whole numbers. For example, palladium hydride is written as PdHx, where x is between 0.02 and 0.58. Many silicate minerals in the Earth's crust and mantle are also non-stoichiometric. These may contain foreign elements trapped in their crystal structures. These substances are related to, but sometimes distinct from, true chemical compounds.
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