Read Chemistry

    ** The (s) and (p) orbitals used in the quantum mechanical description of the carbon atom, were based on calculations for hydrogen atoms. These simple (s) and (p) orbitals do not, when taken alone, provide a satisfactory model for the tetravalent–tetrahedral carbon of methane. ** However, a satisfactory …

  Introduction to Resonance (Resonance in carbonate ion (CO32-)   ** Often more than one equivalent Lewis structure can be written for a molecule or ion. Consider, for example, the carbonate ion (CO32-). We can write three different but equivalent structures, 1–3:   ** Notice two important features of these …

  Percent Composition of Compounds **As we have seen, the formula of a compound tells us the numbers of atoms of each element in a unit of the compound. ** However, suppose we needed to verify the purity of a compound for use in a laboratory experiment. We could calculate …

      ** Organic chemists use a variety of formats to write structural formulas. ** Structural Formulas are written by: (1) Ball-and-stick model (2) Electron-dot formula (lewis structure) (3) Dash formula (4) Condensed formula (5) Bond-line formula ** Examples of these types of structural formulas are shown in  the …

– In this subject, we will discuss the Radioactive decay: Definition, Types, Examples Types of Radioactive Decay – According to the theory put forward by Rutherford and Soddy (1903), radioactivity is a nuclear property. – The nucleus of a radioactive atom is unstable. – It undergoes decay or disintegration by …

– In this subject, we will discuss the Detection and measurement of Radioactivity. Detection and measurement of Radioactivity – Radioactivity can be detected and measured by several methods. – The important ones used in modern practice are listed below. (1) Cloud Chamber  (2) Ionization Chamber (3) Geiger-Muller Counter (4) Scintillation …

  Molecular Mass ** If we know the atomic masses of the component atoms, we can calculate the mass of a molecule. ** The molecular mass: (sometimes called molecular weight) is the sum of the atomic masses (in amu) in the molecule.   ** For example, the molecular mass of …

  Avogadro’s Number (NA) ** Atomic mass units provide a relative scale for the masses of the elements. ** But because atoms have such small masses, no usable scale can be devised to weigh them in calibrated units of atomic mass units. ** In any real situation, we deal with macroscopic …

– In this subject, we will discuss the Atomic Mass and Average Atomic Mass: Definition, Formula, and Calculation Atomic Mass – The mass of an atom depends on the number of electrons, protons, and neutrons it contains. – Knowledge of an atom’s mass is important in laboratory work. – But …

  Nuclear reaction   ** A nuclear reaction is different from a chemical reaction. ** In a chemical reaction, atoms of the reactants combine by a rearrangement of extranuclear electrons but the nuclei of the atoms remain unchanged. ** In a nuclear reaction, on the other hand, it is the …

– In this subject, we will discuss the Formal Charge: Definition, Formula, Calculation, Examples Formal Charge and How To Calculate – Many Lewis structures are incomplete until we decide whether any of their atoms have a formal charge. – Calculating the formal charge on an atom in a Lewis structure …

– In this subject, we will discuss the Lewis Structures: Definition, Overview, Structural Formula, Examples Definition of Lewis structures – A Lewis structure is a structural representation of a molecule where dots are used to show electron positions around the atoms and lines or dot pairs represent covalent bonds between …

– In this subject, we will discuss the Nomenclature of Acids, Bases and Hydrates Nomenclature of Acids – An acid can be described as a substance that yields hydrogen ions (H+) when dissolved in water. (H+ is equivalent to one proton, and is often referred to that way.) – Formulas …

How to Name Molecular Compounds – Unlike ionic compounds, Molecular compounds contain discrete molecular units. – They are usually composed of nonmetallic elements. – Many molecular compounds are binary compounds. – Naming binary molecular compounds is similar to naming binary ionic compounds. – We place the name of the first …

– In this subject, we will discuss the Nomenclature of Ionic Compounds. Naming Compounds – In addition to using formulas to show the composition of molecules and compounds, chemists have developed a system for naming substances based on their composition. – we divided naming substances into three categories: (1) Nomenclature of …

– In this subject, we will discuss Molecular Formulas and Empirical Formulas: Definitions, Examples – Chemists use Chemical formulas to express the composition of molecules and ionic compounds in terms of chemical symbols. – By composition we mean not only the elements present but also the ratios in which the atoms …

– In this subject, we will discuss the Atoms, Molecules, and Ions: Definition, Types, Examples Atoms – Of all the elements, only the six noble gases in Group 8A of the periodic table (He, Ne, Ar, Kr, Xe, and Rn) exist in nature as single atoms. – For this reason, …

– In this subject, we will discuss the Atomic Number, Mass Number, and Isotopes: Definition, Formula, and Calculation Atomic number – All atoms can be identified by the number of protons and neutrons they contain. – The number of protons in the nucleus of each atom of an element is …

MCQ on: Isotopes, Isobars, and Isotones – In this subject, you will find 25 questions and answers MCQ on Isotopes, Isobars, and Isotones.  1. The atoms of an element that have the same number of protons and different numbers of neutrons are called_______ (a) isotopes (b) isobars (c) isotones (d) …

In this subject, the Difference between Isotopes, Isobar, and Isotones will be discussed with some Common Examples for all types. What are Isotopes? Isotopes may be defined as: (1) The atoms of an element that have the same number of protons and different number of neutrons are called Isotopes. (2) …