The fundamental units of matter in the cosmos are atoms and molecules. Maharishi Kand proposed a hypothesis in the year 500 B.C. according to which, if the matter is constantly divided, we shall eventually reach the tiniest particle, known as "pramanu," beyond which further division is not conceivable. Democritus and Leucippus, two ancient Greek philosophers, referred to these particles as atoms. What exactly are atoms and molecules then? Joining Safalta School Online will help you to clear all your doubts.
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Table of Content
Atom and Molecules Definition and Meaning
Properties of Atoms and Molecules
Difference Between Atoms and Molecules
Atoms and Molecules Sample Questions
Which of the following forms of radioactive decay are you familiar with?
Atom and Molecules Definition and Meaning
Atoms and molecules make up matter, which makes up everything in our environment. Anything with mass and space is considered to be matter. It is made up of molecules, which are made up of many atoms, the smallest unit of material.
Definition of an Atom
The smallest component of an element that goes into a compound is called an atom. All compounds, whether or not they have an autonomous life, are thought of as having this as their fundamental structural and functional unit. It nonetheless participates in the chemical process. Atoms in a chemical reaction can only be transformed; they cannot be broken down or created from scratch. Their diameter, which is measured by the nanometer, represents their size.
The smallest unit of the element, tom, is so minuscule that it cannot be seen with the human eye. Protons, neutrons, and electrons are the three basic kinds of particles that make up matter. N, H, He, O, K, etc., as an illustration.
Definition of a Molecules
Molecules are collections of atoms that are chemically linked. It is referred to be the smallest particle of an element (like O2) or compound (like H2O), which can exist alone or in combination. Molecules are stable and exist in a free state. The atoms of a molecule are connected by covalent chemical bonds.
It's possible that the molecules' chemical properties differ from those of the constituent atoms.
Chlorine (Cl) is a poisonous gas, whereas sodium (Na) is a highly reactive metal. These components combine to create sodium chloride (NaCl), often referred to as table salt and which is neither a metal nor a poison.
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Properties of Atoms and Molecules
Properties of Atom
The size of very small atoms is measured in nanometers (1m = 109 nm).
One teaspoon of sugar has the same number of atoms as the total amount of sand grains on all of the world's beaches, to put that into perspective.
Example: The radius of an atom of hydrogen is 10-10 m.
Atomic nuclei are surrounded by electrons in an orbit. These subatomic particles are held together by nuclear links. The tiniest components involved in chemical processes are called atoms.
Whether an atom is stable or unstable depends on how many electrons are present at its highest energy level.
To connect with other atoms, these outermost electrons are either gained or discarded. An atom changes into an ion with a charge when it gains or loses an electron. When an atom gets a positive charge while losing an electron, a cation is created. If an atom adds one additional electron to complete the energy level, it has a negative charge and is known as an anion.
Properties of Molecules
The intermolecular force of attraction largely determines the properties of molecules.
Because the atoms in molecular compounds are joined by a covalent bond, they have low melting and boiling temperatures and may be separated by the application of energy.
These are insoluble in water, but depending on the reaction that occurs when hydrogen binds with them, they may occasionally be sparingly soluble in water.
These do not conduct electricity since they are not split into ions but rather disintegrate into molecules.
Due to the delocalization of electrons, they can flow freely in both solids and liquids since there is insufficient interaction between molecules and electrons.
Difference Between Atoms and Molecules
The following characteristics distinguish atoms from molecules:
- According to Science, an element's atom is the smallest unit that can or cannot exist in a state of freedom. A molecule, on the other hand, is the smallest component of a complex and is constructed from a collection of atoms that are connected by a bond.
- Additionally, an atom may or may not be in a free state. On the other hand, molecules are in a state of freedom.
- An atom also contains electrons and a nucleus, which is composed of protons and neutrons. On the other hand, a molecule is composed of two or more separate or related atoms that are bonded together chemically.
- An atom also has a spherical shape. On the other hand, a molecule's shape might be angular, rectangular, triangular, or linear.
- The fact that atoms engage in chemical processes without chemically breaking down is essential. A molecule, on the other hand, is less reactive and doesn't take part in chemical processes.
- The electrical pull between the electron and the nucleus helps keep atoms' nuclear bonds strong. On the other hand, molecules share electrons through covalent bonds, which allows them to remain bound together.
Atoms and Molecules Sample Questions
Once you have finished reading the whole chapter, practise the example questions by answering them.
- What is the atomicity of benzene, graphite, ozone, chlorine, and sulphur?
- How much water, in moles, weighs?
- Is benzene a molecule or an atom? Identify its mass.
- Why do polyatomic ions exist? Give instances.
Which of the following forms of radioactive decay are you familiar with?
- When the nucleus emits an alpha particle, a helium nucleus with two protons and two neutrons, the process of alpha decay starts. A new element with a lower atomic number forms as a result of the emission.
- The beta decay (and electron capture) that results from a neutron becoming a proton or a proton becoming a neutron is caused by the weak force.
- Gamma decay, which results in the emission of electromagnetic radiation, is brought on by a change in the energy level of the nucleus to a lower state.
What distinguishes an atom from a molecule?
The smallest component of a chemical element is referred to as an atom. A collection of two or more atoms that are bound together by chemical bonds is referred to as a molecule
What number of atoms make up a molecule/
A molecule is a collection of two or more atoms that are joined by chemical bonds. So a molecule needs at least 2 atoms to form.
Can you make an atom?
Atoms cannot be created or destroyed, it is challenging to break them up into smaller parts. The Law of Mass Conservation served as the foundation for this. Atoms may split apart into smaller fragments, as was subsequently found. Chemical reactions are required for the division, blending, or rearranging of atoms.
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