Fun with Chemistry

 Discovery of Neutron: Rutherford observed that atomic mass of the element could not be explained onvthe basis of the masses of electron and proton only. He predicted in 1920 that some neutral particle having mass equal to that of proton must be present in an atom. Thus scientists were in search of such a neutral particle. Eventually in 1932 Chadwick discovered neutron, when he bombarded alpha particles on a beryllium target. Hobserved that highly penetrating radiations were produced. These radiations were calleneutron. Properties of neutron are as following: i. Neutrons carry no charge i.e. they are neutral. ii. They are highly penetrating. iii. Mass of these particles was nearly equal to the mass of a proton.

 Discovery of Proton: In 1886 Goldstein observed that in addition to cathode rays, other rays were also present in the discharge tube. These rays were traveling in opposite direction to cathode rays. He used a discharge tube having perforated cathode. He found that these rays passed through holes present in the cathode and produced a glow on the walls of the discharge tube. He called these rays as "canal rays". The properties of these rays were as following: i. These rays travel in straight lines in a direction opposite to the cathode rays. ii. Their deflection in electric and magnetic field proved that these are positively charged.  iii. The nature of canal rays depends upon the nature of gas, present in the discharge tube. iv. These rays do not originate from the anode. In fact these rays are produced when the cathode rays or electrons collide with the residual gas molecules present in the discharge tube and ionize them as follows: v. Mass of these particles was found equal

 Even as scientists were confirming the existence of the atoms, they discovered another layer of complexity below atoms. Atoms are made of still smaller particles. Studies of electricity suggested there needed to be something that you could transfer, that carried charge. It was the work of J.J. Thomson, Ernest Rutherford among others that led to advancements in our knowledge of atomic structure. According to Dalton, an atom is an indivisible, hard,dense sphere. Atoms of the same element are alike. They combine in different ways to form compounds. In the light of Dalton's atomic theory, scientists performed a series of experiments. But in the late 1800's and early 1900's, scientists discovered new subatomic particles.  •In 1886, Goldstein discovered positively charged particles called protons.  •In 1897, J.J. Thomson found in an atom, the negatively charged particles known as electrons. It was established that electrons and protons are fundamental particles of matter. Based

 Hello readers! I hope you all will be fine and enjoying my blogs. Today we discuss about Avogadro's number.  Avogadro's Number is a collection of 6.02×10 ²³  particles.It is represented by symbol 'NA'. Hence, the 6.02×10 ²³  number of atoms, molecules or formula units is called Avogadro's number that is equivalent to one 'mole' of respective substance. In simple words, 6.02×10 ²³  particles are equal to one mole as twelve eggs are equal to one dozen. To understand the relationship between the Avogadro's number and the mole of a substance let us consider a few examples. i.6.02×10 ²³  atoms of carbon are equivalent to one mole of carbon. ii. 6.02×10 ²³  molecules of H2O are equivalent to one mole of water. iii. 6.02×10 ²³  formula units of NaCl are equivalent to one mole of sodium chloride.  Thus, 6.02×10 ²³  atoms of elements or 6.02×10 ²³  molecules of molecular substance or 6.02×10 ²³  formula units of ionic compounds are equivalent to 1 mole.

 A mole is defined as the amount(mass) of a substance that contains  6.022 × 10²³ number of particles (atoms, molecules or formula units). It establishes a link between mass of a substance and number of particles as shown in summary of molar calculations. •It is abbreviated as 'mol'. Mass of a substance is either one of the following: atomic mass, molecular mass or formula mass. These masses are expressed in atomic mass units (amu). But when these masses are expressed in grams, they are called as molar masses.  •Scientists have agreed that Avogadro's number of particles are present in one molar mass of a substance. Thus, quantitative definition of mole is the atomic mass, molecular mass or formula mass of a substance expressed in grams is called mole. For example: Atomic mass of carbon expressed as 12 g = 1 mol of carbon Molecular mass of H2O expressed as 18 g = 1 mol of water Molecular mass of H2SO4 expressed as 98 g = 1 mol of H2SO4 Formula mass of NaCl expressed as 58.5

 A molecule is formed by the chemical combinations of atoms. It is the smallest unitbof a substance. It shows all the properties of the substance and can exist independently. There are different types of molecules depending upon the number and types of atoms combining. A few types are discussed here. Monoatomic Molecules: A molecule consisting of only one atom is called monoatomic molecule. For example, the inert gases helium, neon and argon all exist independently in atomic form and they are called monoatomic molecules. Diatomic Molecules: If a molecule consists of two atoms, it is called diatomic molecule. For example: hydrogen (H ), oxygen (O2), chlorine (Cl ) and hydrogen chloride (HCl). Triatomic Molecules: If it consists of three atoms, it is called triatomic molecule. For example :H2O and CO2.  Poly atomic Molecules: If a molecule consists of many atoms, it is called polyatomic. For example: methane (CH4), sulphuric acid (H2SO4 ) and glucose (C6H12O6).  Homoatomic Molecules:

  Hello! Welcome to my blog. Today we will discuss about chemical species. lets start. If one  molecule  is identical to another, we can say they are the same chemical species. Ion: It is an atom or group of atoms having a charge on it. The charge may be positive or negative.  There are two types of ions:       Cations: An atom or group of atoms having positive charge on it is called cation. They are formed when atoms lose electron from their valance shells. Examples:   Ca 2+   Ag +    Al 3+     H 3 O +     NH 4 +     Hg 2 +2      Fe +2     Fe  +3        Anions: An atom or group of atoms having negative charge on it is called anion. They are formed by gain or addition of electron to an atom. Examples: Cl –    OH –      I –     Cr 2 O 7 -2     O -2      SO 4 -2 Molecular Ion: When a molecule loses or gain electron it forms a molecular ion. Free Radical: These are atoms or groups of atoms possessing odd number of unpaired electrons. It is represented by putting a dot over the symbol of a