It is often useful to follow chemical reactions by looking at changes in the oxidation numbers of the atoms in each compound during the reaction. Oxidation numbers also play an important role in the systematic nomenclature of chemical compounds. By definition, the oxidation number of an atom is the charge that atom would have if […]
In chemistry, a compound is a substance that results from a combination of two or more different chemical element s, in such a way that the atom s of the different elements are held together by chemical bonds that are difficult to break. These bonds form as a result of the sharing or exchange of
ISOTOPE Isotopes Definition: Isotopes are atoms with the same number of protons, but differing numbers of neutrons. Isotopes are different forms of a single element. Examples: Carbon 12 and Carbon 14 are both isotopes of carbon, one with 6 neutrons and one with 8 neutrons (both with 6 protons). ATOMIC WEIGHTS AND ISOTOPIC ABUNDANCE
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Atoms are the basic units of matter and the defining structure of elements. Atoms are made up of three particles: protons, neutrons and electrons. Protons and neutrons are heavier than electrons and reside in the center of the atom, which is called the nucleus. Electrons are extremely lightweight and exist in a cloud orbiting the
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A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound. Molecules are made up of atom s that are held together by chemical bonds. These bonds form as a result of the sharing or exchange of electron s among atoms. The atoms of
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Element Definition: A chemical element is a substance that cannot be broken down by chemical means. Elements are defined by the number of protons they possess. These are the first 20 elements, listed in order: 1 – H – Hydrogen 2 – He – Helium 3 – Li – Lithium 4 – Be – Beryllium
In our daily life, we come across many objects, the knowledge about which can be gained by one or more of our senses like sight, touch, hearing, taste and smelling. These objects possess mass, occupy space and may have different shapes, sizes and colours. All these objects constitute matter. Matter may thus, be defined as
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Chemistry as a Subject and as a Central Science CHEMISTRY AS A DISCIPLINE Human mind has always been very curious to make investigations and know about various activities/phenomena occurring around him. This curiosity has led him to collect information through experiments and observations. The curious mind has also been responsible for the research activities of
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ORBITALS OF THE ATOM The region in space within which there is maximum possibility of finding an electron in an atom is called an ATOMIC ORBITAL. We have s, p, d, and f orbitals. Shapes of s and p orbitals are as follows:
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CONSTITUENTS OF AN ATOM Atoms are made up of sub-particles. Protons, electrons and neutrons. Proton has a positive charge, electron has a negative charge and neutron has no charge. Atomic number and mass number The atomic number of an element is the number of protons in the nucleus of its atom. Mass number or
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NAMING OF BINARY COMPOUNDS Nomenclature: This is the system of naming chemical compounds. The system is called IUPAC (International union of pure and applied chemistry). The naming is determined by the constituent elements in the compound and the oxidation number if necessary. In naming binary compounds (compounds with only two elements), electropositive elements (cations) are
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ATOMS AND MOLECULES Matter is made up of discrete particles. The main ones are atoms, molecules, and ions. An atom is the smallest part of an element which can take part in a chemical reaction. A molecule is the smallest particle of a substance that can exist alone and still retains the chemical properties of
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STANDARD SEPARATION TECHNIQUES The importance of separating a mixture into its constituents cannot be over emphasized since most substances are needed in their pure form. There are many standard separation techniques. Some of these separating techniques are filtration, centrifugation and decantation. Others include sieving, magnetic separation and sublimation, evaporation, crystallization, fractional precipitation, distillation, fractional distillation,
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COMPOUND A Compound is a substance which contains two or more elements chemically combined together. A compound is formed as a result of chemical change. Examples of compounds are Compound Constituent Elements Water Hydrogen, oxygen Sand silicon, oxygen Limestone calcium, carbon, oxygen Common salt sodium, chlorine Ethanol carbon, hydrogen, oxygen PROPERTIES OF A COMPOUND
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ELEMENTS AND SYMBOLS An element is a substance which cannot be split into simpler units by ordinary chemical process. There are over one hundred known elements. SYMBOLS OF ELEMENTS There are three ways in which symbols of elements are derived. From the first letter of the name of the element Element Symbols Hydrogen
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Matter is anything that has weight and occupies space. It exists in three states namely: solid, liquid and gas. The fundamental difference between the three states of matter depends on the degree of movement of the particles they are made of. SOLID STATE The particles of a solid are tightly packed and held together by
DEFINITION OF LABORATORY A laboratory is a room or building equipped for scientific experimentation or research. It is a special facility where experiments are done and typically contains scientific equipment and apparatus. LABORATORY APPARATUS Laboratory apparatus refers to the various tools or equipment used by scientists working in the laboratory. Some common laboratory apparatuses
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CHEMISTRY AS A SCIENCE SUBJECT Science is an organized body of knowledge gathered through systematic experimentations and philosophical observations. Chemistry can be defined as a branch of science which deals with the study of the nature, structure, composition, properties and uses of all forms of matter and the changes in structure and composition which matter
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Charge flow during electrolysis The coulomb is the electrolytic unit of charge. A current of one ampere is the rate of flow of charge equal to one coulomb per second. The charge is calculated from the knowledge of the number of seconds for which a steady current is passed. Current in circuit Time taken Total
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The importance of electrochemical cells or galvanic cells lies in their ability to provide us with a portable source of electrical energy. We have already studied that indirect redox reaction is, primarily, the basis of all the electrochemical cells Quite often, we use the term battery to represent the arrangement of two or more galvanic
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