All matter in this universe is made up of elements and each element is considered as a chemical. Elements interact with each other and form bond to make molecules. When these molecules interact with each other then reactants are changed into products and this phenomenon is termed as chemical reaction. These are the reactions by … Read more

  Atoms are the fundamental building blocks of the matter. Atoms are extremely small in size; typical its sizes are around 100 Pico meters . Every solid, liquid, gas, is composed of neutral or ionized atoms. Every atom has a nucleus and one or more electrons bound to the nucleus. Protons——————— Positive charge; Neutrons——————–No charge; Electrons———————- Negative charge. Structure of an Atom: Structure of an … Read more

The model of Valence Shell Electron Pair Replication is oftentimes abbreviated as VSEPR (known as “Vesper”). It is fundamentally a model which predicts a molecule’s geometry. In particular, VSEPR models see the molecular geometry and bonding of polyatomic ions and organic molecules. It is beneficial for almost the whole of the compounds that possess a … Read more

  VB or Valence Bond theory presumes that the whole of the bonds are “localized bonds” which are formed between 2 atoms by donating an electron from each of the atoms. This is indeed a false assumption as several atoms bond with the use of delocalized electrons. As per the prediction in Molecular oxygen (O2) … Read more

Resonance Resonance dictates the method that is within the VB theory or Valence Bond Theory of bonding and the way of detailing the “delocalized electrons” within some molecules. Here, the bonding is not particularly described out by a lone Lewis structure. It definitely contrasts and compares two or more than two potential Lewis structures which … Read more

  As per the modern periodic law, the elements are arranged in increasing order of atomic numbers of elements since their properties are the periodic function of the atomic number. This law was postulated by Henry Mosely in 1913 using X-ray analysis. This table consists of 18 groups and 7 periods wherein, period indicates the … Read more

A brief history of the development of the periodic table The development of periodic table dates back to over 200 century of growth in the understanding of atoms, atomic theory and the discovery of atomic masses of the elements. It was in the year 1869 that Dmitri Mendeleev published the periodic table however his work … Read more

In the early 1800s, the chemists were aware of only 30 elements, but with the development of nuclear physics, scientists are now able to identify more and more elements present on the earth. Based on the IUPAC standards, the current periodic table contains 118 elements. Among these elements, 92 are natural elements and the remaining … Read more

Symmetrical distribution of electrons allows half and completely filled subshells to become more stable. Two or more electrons with the same spin can exchange their position with the degenerate orbitals. The spinning of electrons introduces a new type of quantum mechanical interaction called Exchange energy, Eex. And, the exchange energy release is maximum in the … Read more

The atomic theory has evolved with the discovery of electrons, protons and neutrons and incorporated dual behavior of matter to propose a quantum mechanical model. An important section of this theory is the placement of electrons that surround the nucleus. Figure 1: Evolution of atom from Billard ball model (1804), Plum pudding model (1897), Rutherford … Read more