How many elements are present in the periodic table? A total of 118 elements are present in the periodic table. What is the meaning of ionisation enthalpy? The enthalpy change associated with the removal of the original electron from an atom with a single gas in its ground surface is called as the first ionization… Continue reading FAQs
Month: July 2022
Few Important Questions
What is the difference between Modern Periodic Law and Mendeleev’s Periodic Law? What is the ionic radius? What is the atomic radius? What is isoelectronic species? Give an example. Elements in the same group have similar chemical and physical properties.
Introduction
In this chapter, we will discuss the development of the periodic table and the periodic law. The arrangement of elements in the modern periodic table is organized into eight vertical columns (groups) and seven horizontal rows (periods) based on their atomic number. Based on the electronic configuration, elements can be classified into four types in… Continue reading Introduction
Few Important Questions
1. Calculate the wavenumber and frequency for the below: Yellow light emitted from a sodium lamp has a wavelength (λ) of 580 nm 2. Calculate and provide the number of electrons for the following: H+2 O+2 H2 3. Calculate the wavelength using the following details: Mass of electron is 9.1 × 10–31 kg and K.E. is… Continue reading Few Important Questions
Common terminologies used
Electrons – These subatomic particles orbit around the nucleus. They are negatively charged particles and found in definite energy levels orbiting the nucleus. Protons – Theses subatomic particles are found in the nucleus. They are positively charged particles and belong to the nucleons group. Neutrons – Theses subatomic particles are found in the nucleus. They… Continue reading Common terminologies used
Introduction
As discussed in the previous chapter, according to Dalton’s atomic theory, atoms are the building blocks of matter. In the year 1808, John Dalton proposed atomic theory saying that atom is an indivisible particle of matter. By the end of the nineteenth century, experiments proved that atoms comprise of three particles viz protons, neutrons, and… Continue reading Introduction
FAQs
How to make the subject Chemistry easy for children? Chemistry involves many equations and thus conceptual teaching can help students develop interest towards this subject. What is matter? Anything has occupies space and has mass can be defined as matter in Chemistry. Should a student be good in Maths to solve the CBSE Class 11… Continue reading FAQs
Few Important Questions
Define mass and write its SI unit? Calculate the number of atoms in 52 moles of Ar and 52 g of He. What is the mass per cent of elements present in Na2SO4 What is the difference between 0.50 mol Na2CO3 and 0.50 M Na2CO3
Laws Of Chemical Combination
There are five basic laws that govern the chemical combination of elements. They are as follows: Law of Conservation of Mass It states that during a chemical reaction, the mass of the products and reactants will always be equal. Law of Definite Proportions It states that every chemical compound will contain a fixed and constant… Continue reading Laws Of Chemical Combination
Introduction
Chemistry is referred to as the “Central Science” as it interconnects geology, biology, environmental science, and physics to each other. Ancient Indians had knowledge of various concepts from chemistry even before it emerged as a discipline. In chemistry, one of the core fundamental concepts is matter – it is defined as a substance that occupies… Continue reading Introduction