*REDOX REACTIONS*
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Here, we will discuss about the different definitions of oxidation and reduction (redox) in terms of oxygen transfer, hydrogen and electrons. We will as well talk about oxidizing agent and reducing agent.
Definitions of oxidation and reduction in terms of oxygen transfer
โข Oxidation is addition of oxygen.
โข Reduction is removal of oxygen.
For instance, in the extraction of iron from its ore:
Due to the fact that reduction and oxidation are going on side-by-side, this is known as a redox reaction meaning oxidation-reduction reaction.
Oxidising and reducing agents
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An oxidizing agent is a substance that oxidizes another thing else. In the example above, the iron (III) oxide is the oxidizing agent.
A reducing agent is a substance that reduces something else. In the above equation, the carbon monoxide is acting as the reducing agent.
โข Oxidizing agents provide oxygen to another substance.
โข Reducing agents take out oxygen from another substance.
Oxidation and reduction in terms of hydrogen transfer
โข Oxidation is the loss of hydrogen from a compound.
โข Reduction is gain of hydrogen by a compound.
These definitions you would notice are precisely the reverse of the definition of oxidation and reduction in terms of oxygen.
For instance, ethanol can be oxidized to ethanal:
In other to remove the hydrogen from the ethanol, you would need to make use of oxidizing agent. A regularly used oxidizing agent is potassium dichromate (VI) solution that is acidified with dilute sulphuric acid.
Ethanal can as well again be reduced back to ethanol through the addition of hydrogen to it. A potential reducing agent is sodium tetrahydridoborate, NaBH4. Again, the equation is excessively complex to be worth troubling about at this level.
As a summary:
โข Oxidizing agents provide oxygen to a different substance or take away hydrogen from it.
โข Reducing agents take away oxygen from another substance or provide hydrogen to it.
Oxidation and reduction in terms of electron transfer
โข This is simply the most significant application of the oxidation and reduction at Aโ level.
โข Oxidation is defined as electron loss.
โข Reduction is defined as electron gain.
It is necessary that you have these definitions in mind. There is a extremely simple way to accomplish this.
An example is shown below:
The equation illustrates an uncomplicated redox reaction which can perceptibly be explained in terms of oxygen transfer.
Copper (II) oxide and magnesium oxide are mutually ionic. The metals evidently are not. If you rephrase this as an ionic equation, it turns out that the oxide ions are bystander ions that you are left with:
A last remark on oxidizing and reducing agents
In the equation above, the magnesium is reducing the copper (II) ions by donating electrons to them to neutralize the charge. Magnesium is acting as a reducing agent.
Looked at in another way, the copper (II) ions are extracting electrons from the magnesium to generate the magnesium ions. The copper (II) ions are working as an oxidizing agent.
Oxidizing and Reducing Agents
An oxidizing agent or oxidant is a substance that gains electrons and is reduced in a chemical reaction. The oxidizing agent is also known as electron acceptor, the oxidizing agent is usually in one of its top probable oxidation states due to the fact that it will gain electrons and be reduced. Examples of oxidizing agents are halogens, potassium nitrate, and nitric acid.
A reducing agent or reductant is a substance that loses electrons and is oxidized in a chemical reaction. A reducing agent is normally in one of its lesser possible oxidation states and is referred to as the electron donor. A reducing agent would normally be oxidized due to the fact that it loses electrons in the redox reaction. Examples of reducing agents are the earth metals, formic acid, and sulfite compounds.
A reducing agent reduces other substances and loses electrons; consequently, its oxidation state will amplify. An oxidizing agent oxidizes other substances and gains electrons
*CHEMICAL BONDING*
There are numerous types of chemical bonds and forces acting jointly to combine molecules together. The two most fundamental types of bonds are ionic and covalent bond. In ionic bonding, atoms transfer electrons to each other. Ionic bonds need at least one electron donor and one electron acceptor. On the contrary, atoms that have similar electro negativity share electrons through covalent bonds as for such atoms, donating or receiving electrons are not favorable.
Chemical bonding is a means through which atoms unite to form molecules. Chemical bond exists between two atoms or groups of atoms when the forces acting between them are physically powerful enough to result to the formation of an aggregate with adequate stability to be termed an autonomous species. The no of bonds an atom forms matches up to the number of electron at its outer shell. Bond energy is the quantity of energy necessary to break a bond and create neutral atoms. In line with Coulombโs law every bond as a result of attraction that exist between unlike charges. On the other hand, the manner this force is manifested varies depending on the atoms concerned. The main types of chemical bond are the ionic, covalent, metallic, and hydrogen bonds. The ionic and covalent bonds are ideal forms but the majority of the bond types are of an intermediary type.
Bonding energy between two atoms
The interaction energy between two atoms at equilibrium is referred to as the bonding energy between the two atoms. To break the bond, this energy must be supplied from outside. Breaking the bond means that the two atoms become infinitely separated. In real substances that are made up of varieties of atoms, bonding is calculated by stating the bonding energy of the entire substances in terms of the disjointing distances among all atoms. There are different types of bonding:
โข Primary bonding: Ionic (involves transfer of outermost electrons)
โข Covalent (involves sharing of outermost electrons, directional)
โข Metallic (involves delocalization of valence electrons)
โข Secondary or van der Waals Bonding:(widespread, but less strong than primary bonding)
โข Dipole-dipole
โข H-bonds
โข Polar molecule-induced dipole
โข Variable dipole (the most weak bond)
The Ionic Bonding
Ionic bonding is the total transfer of outermost electron(s) between atoms. It is the type of chemical bond that produces two oppositely charged ions. In ionic bonds, the metal loses electrons to turn into a positively charged cation, while the non-metal receives those electrons to turn into a negatively charged anion. For ionic bond to occur there must be an electron donor, metal, and an electron acceptor, non metal.
Ionic Bonding is occurs because metals have a small number of electrons in their outmost orbital. Through the loss of those electrons, these metals can attain noble-gas configuration and meet the octet rule. Likewise, non metals that have nearly 8 electrons in their outermost shell have the tendency of readily accepting electrons to attain their noble gas configuration. In ionic bonding, over 1 electron can be donated or received to fulfill the octet rule. The charge on the anion and cation matches up with the number of electrons contributed or received. In ionic bonds, the net charge of the compound must be zero.
The ionic bond is a chemical bond formed as a result of attraction between two opposite charged ions. The atoms of metallic elements like sodium easily lose their valence electrons, whereas the atoms of non-metals like chlorine have the tendency to gain electrons. The reaction between them results to a highly stable ions which maintain their individual structures while approaching one another to form a stable molecule or crystal. In an ionic crystals such as sodium chloride, no separate diatomic molecules are present; instead, the crystal is made up of composed of independent Na+ and Clโ ions, with each being attracted to adjoining ions of the opposite charge giving rise to one single gigantic molecule.
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The covalent bond
The covalent bond
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*STRUCTURE OF THE ATOM*
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Matter is anything that has mass and occupies space. Atoms are fundamental building blocks of matter that cannot be further divided by any chemical means. What are elements?
Elements are constituents of matter. There are 92 natural elements. Elements like hydrogen, carbon, nitrogen and oxygen are elements that make up the majority of living things. Other groups of element that exist in living things are: magnesium, calcium, phosphorus, sodium, potassium.
Many elements were discovered before the late 1800โs. A Russian scientist Dmitri Mendeleev then proposed an arrangement of elements based on their atomic masses. In the modern time, elements are no longer arranged based on their atomic masses but according to their atomic numbers.
The word atom is a derivative of the Greek word atom which means undividable. The Greeks came to a conclusion that matter could be further divided into particles that are too tiny to be seen with the naked eye. These tiny indivisible particles of matter were referred to as atoms.
An atom is made up of three types of particles:
โข Protons
โข Neutrons, and
โข Electron.
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The nucleus of an atom is made up of protons and neutrons. The electron of an atom resolves round the nucleus of an atom in an orbit known as shells.
Neutrons are neutral and have no electrical charge while protons and electrons are electrically charged. While Protons are positively charged and have a relative charge of +1, electrons are negatively charged with a relative charge of -1.
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The number of protons in the nucleus of an atom is known as its atomic number. Atoms are arranged in atomic number order in the periodic table while electrons are arranged in energy levels or shells. Each energy level holds a definite numbers of electrons.
The electronic structure of an atom is an explanation of the manner the electrons are arranged, which can be demonstrated in a diagram or through numbers. The position of an element in the periodic table and its electronic structure interrelated.
The atomic mass of an element is greatly determined by the number of protons and neutrons in its nucleus. For instance, in a mass number of 150; 149 lbs which equivalent to 15 oz is protons and neutrons while only 1 oz. is the electronโs mass. The mass of an electron is extremely small – 9.108 X 10-28 grams.
It is the number of protons in an atom that establishes the atomic number. For example, Hydrogen is with an atomic number of 1.The number of protons in an element is invariable (example, the number of proton in Hydrogen (H) =1 and that of Uranium (Ur) = 92 but the number of neutron may well differ, therefore the mass number (protons + neutrons) of an element could differ.
A particular element may have differing numbers of neutrons; the different forms of an element with the same number of proton but with differing numbers of neutron are referred to as isotopes. Isotopes have the same chemical properties but the physical properties of a number of isotopes might be different.
Some isotopes are radioactive in nature. This means that give out energy while they decompose and break down to a more stable form. This gives rise to another element.
Half-life of a radioactive element is the time that it takes for half of the atoms of that element to decay into stable form. An example of element that exhibits isotopy is oxygen. The element-Oxygen with an atomic number of 8 may possibly have 8 or 9, or 10 neutrons.
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Atomic Symbols and Isotopes by SHINING STARS
The atom of every element is composed of electrons, protons and neutrons. Atoms of the same element possess the same number of protons and electrons but the number of neutrons can vary. When the neutrons vary such elements are referred to as isotopes. Due to these isotopes, it got crucial to formulate a notation to differentiate an isotope from the other. This notation is known as the atomic symbol. The atomic symbol is usually denoted with three different letters:
1. The X: This is used to represent the element.
2. The A: This is a symbol that represents the atomic num
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