What Is A Short Note On Atoms And Molecules Class 9

What is a short note on atoms and molecules Class 9?

A molecule is defined as the smallest unit of a compound that contains the chemical properties of the compound. Molecules are made up of groups of atoms. Describing the structure of an atom, an atom is also sub-divided into smaller units. Proton, electrons, and neutrons are sub-particles of an atom.

What is atom Class 9 notes?

According to Dalton, an atom may be defined as the simplest particle of a matter that takes part in chemical reactions. However, modern researches have conclusively proved that atom is no longer on indivisible particle, it has been broken into smaller fragments like electrons, proton and neutrons.

How to introduce the chapter atoms and molecules in class 9?

Atom and Molecule of Class 9 Atom means unable to be divided. Demokritos thought that this world is made of the atoms which are moving in the empty which spread infinitely. On the other hand, Aristoteles (Ancient Greece, B.C. 384 – 322) thought that the world is filled with continuous substances.

What is the atomic mass Class 9 notes?

An atom is made up of electrons, protons, and neutrons. The atomic mass is the total mass of all protons, neutrons, and electrons in the atom. But, since the mass of the electron is lesser than the mass of proton and neutron, the atomic mass is the mass of protons and neutrons.

What are the 4 types of atoms?

So… what makes atoms different from one another? Well, let’s take a look at hydrogen, oxygen, carbon, and nitrogen, the four most common elements in the solar system.

What are the 5 parts of an atom?

Atoms consist of three basic particles: protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the atom are called electron shells and contain the electrons (negatively charged).

What is valency Class 9?

Valency is simply equal to the number of electrons gained, lost or shared by an atom of an element to achieve the nearest noble gas configuration. For example, the valency of sodium (Na) is 1, magnesium (Mg) is 2, Chlorine (Cl) is 1 etc.

What is called atom?

An atom is a particle of matter that uniquely defines a chemical element. An atom consists of a central nucleus that is surrounded by one or more negatively charged electrons. The nucleus is positively charged and contains one or more relatively heavy particles known as protons and neutrons.

Who named atom class 9?

There was a brilliant philosopher named Democritus (around 400 B.C.), and he proposed the Greek word atomos, which means uncuttable. And so as he explained, all matter was eventually reducible to discrete, small particles or atomos. The word atom arrived from this Greek word.

What is important in atoms and molecules Class 9?

Atoms are indivisible particles, which cannot be created or destroyed in a chemical reaction. Atoms of a given element are identical in mass and chemical properties. Atoms of different elements have different masses and chemical properties. Atoms combine in the ratio of small whole numbers to form compounds.

What are the important points of atom and molecules?

Ans: An atom is a microscopic particle of a chemical element that may or may not exist independently. Molecules are the smallest unit in a complex, consisting of a group of atoms that the bond links together. Chemical bonds exist between two or more identical atoms or atoms of different kinds.

What is chemical formula Class 9?

The chemical formula of a compound means the symbolic representation of the composition of a compound. A chemical formula for a molecule is represented by the group of symbols of the elements that constitute the molecule, and the number of atoms of each element present in one molecule.

What is the mass of oxygen?

What is formula of atomic mass?

Atomic mass can be calculated by the sum of the mass number of protons, electrons, and neutrons. We can determine the relative atomic mass of an atom also with the help of atomic mass. It is calculated by the average mass of the isotope of that element divided by the mass of the Carbon – 12 atom.

What is isotopes Class 9?

Atoms with the same number of protons but different numbers of neutrons are called isotopes. They share almost the same chemical properties, but differ in mass and therefore in physical properties.

What is a short note on atoms and molecules?

Particles can be atoms, molecules or ions. Atoms are single neutral particles. Molecules are neutral particles made of two or more atoms bonded together. An ion is a positively or negatively charged particle.

What is atom and molecule with example class 9?

Atoms may or may not have matter properties whereas molecules have matter properties. 5. Examples of atoms are hydrogen, oxygen, nitrogen etc. Examples of molecules are H2 and O2 etc.

What is the short note of atom?

An atom is a particle of matter that uniquely defines a chemical element. An atom consists of a central nucleus that is surrounded by one or more negatively charged electrons. The nucleus is positively charged and contains one or more relatively heavy particles known as protons and neutrons.

What are the short notes of molecules?

A molecule is two or more atoms connected by chemical bonds, which form the smallest unit of a substance that retains the composition and properties of that substance. Molecules form the basis of chemistry. Molecules are noted with the element symbol and a subscript with the number of atoms.