Category: Ch 3 – Atoms And Molecules

Compounds When two or more elements chemically combine in a fixed ratio by mass, the obtained product is known as a compound. Compounds are substances consisting of two or more different types of elements in a fixed ratio of its atoms. Ions An ion is defined as an atom or molecule which has gained or… Continue reading Writing Chemical Formulae

Molecules and Atomicity A molecule is defined as the smallest unit of a compound that contains the chemical properties of the compound. The atomicity of an element is the number of atoms in one molecule of the element. For e.g:- Hydrogen, nitrogen, oxygen, chlorine, iodine, bromine all have two atoms in each of their molecules. So, the… Continue reading Atomic Valency

Mole concept & Avogadro Number In a substance, the amount of entities present for e.g. atoms, molecules, ions, is defined as a mole. A mole of any substance is 6.022×1023 molecules. Mole concept is one of the most convenient ways of expressing the amount of reactants and product in the reaction. The value of Avogadro’s number… Continue reading Mole Concept

The smallest identifiable unit into which a pure substance may be divided while retaining its composition and chemical properties is a molecule, which is a collection of two or more atoms. Molecules of elements A molecule is a collection of two or more chemically bound atoms, whether they are from the same element or another.… Continue reading Molecule

Molecular mass of an element is defined as the sum of the masses of the elements present in the molecule. Molecular mass is obtained by multiplying the atomic mass of an element with the number of atoms in the molecule and then adding the masses of all the elements in the molecule.

Atomic mass and atomic mass unit Atomic mass is the total of the masses of the electrons, neutrons, and protons in an atom, or in a group of atoms, the average mass. Mass of an atomic particle is called the atomic mass. This is commonly expressed as per the international agreement in terms of a… Continue reading Atomic Mass

According to Dalton’s atomic theory, atoms, which are indestructible and indivisible building blocks, make up all substances. Unlike other elements, which have atoms of different sizes and weights, an element’s atoms have all the same size and mass. Dalton proposed that the concept of atoms could be used to explain the laws of conservation of… Continue reading Dalton`s Atomic Theory

An atom is the defining structure of an element, which cannot be broken by any chemical means. The atomic symbol has three parts:- The symbol X: the usual element symbol The atomic number A: equal to the number of protons The mass number Z: equal to the total number of protons and neutrons in an… Continue reading Atoms

Chemical Reactions In a chemical reaction, two or more molecules interact to produce new compounds and are called reactants, whereas the newly formed compounds are called products. In a chemical reaction, a chemical change must occur, which is generally observed with physical changes like precipitation, heat production, colour change, etc. Law of conservation of mass… Continue reading Laws of Chemical Combination

Atoms and molecules are responsible for forming tiny sand particles, gargantuan black holes and everything in between. The atom is the most fundamental unit of matter, making up everything that we see around us. It is extremely small, measuring in at less than 0.1 to 0.5 nanometers.