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From Wikipedia

Ionic bond

An ionic bond is a type of chemical bond that involves a metal and a nonmetalion (or polyatomic ions such as ammonium) through electrostatic attraction. In short, it is a bond formed by the attraction between two oppositely charged ions.

The metal donates one or more electrons, forming a positively charged ion or cation with a stable electron configuration. These electrons then enter the non metal, causing it to form a negatively charged ion or anion which also has a stable electron configuration. The electrostatic attraction between the oppositely charged ions causes them to come together and form a bond.

For example, common table salt is sodium chloride. When sodium (Na) and chlorine (Cl) are combined, the sodium atoms each lose an electron, forming cations (Na+), and the chlorine atoms each gain an electron to form anions (Cl−). These ions are then attracted to each other in a 1:1 ratio to form sodium chloride (NaCl).

Na + Cl → Na+ + Cl−→ NaCl

The removal of electrons from the atoms is endothermic and causes the ions to have a higher energy. There may also be energy changes associated with breaking of existing bonds or the addition of more than one electron to form anions. However, the attraction of the ions to each other lowers their energy. Ionic bonding will occur only if the overall energy change for the reaction is favourable – when the bonded atoms have a lower energy than the free ones. The larger the resulting energy change the stronger the bond. The low electronegativity of metals and high electronegativity of non-metals means that the energy change of the reaction is most favorable when metals lose electrons and non-metals gain electrons.

Pure ionic bonding is not known to exist. All ionic compounds have a degree of covalent bonding. The larger the difference in electronegativity between two atoms, the more ionic the bond. Ionic compounds conduct electricity when molten or in solution. They generally have a high melting point and tend to be soluble in water.

Ionic structure

Ionic compounds in the solid state form lattice structures. The two principal factors in determining the form of the lattice are the relative charges of the ions and their relative sizes. Some structures are adopted by a number of compounds; for example, the structure of the rock salt sodium chloride is also adopted by many alkali halides, and binary oxides such as MgO.

Strength of an ionic bond

For a solid crystalline ionic compound the enthalpy change in forming the solid from gaseous ions is termed the lattice energy. The experimental value for the lattice energy can be determined using the Born-Haber cycle. It can also be calculated using the Born-Landé equation as the sum of the electrostatic potential energy, calculated by summing interactions between cations and anions, and a short range repulsive potential energy term. The electrostatic potential can be expressed in terms of the inter-ionic separation and a constant (Madelung constant) that takes account of the geometry of the crystal. The Born-Landé equation gives a reasonable fit to the lattice energy of e.g. sodium chloride where the calculated value is −756 kJ/mol which compares to −787 kJ/mol using the Born-Haber cycle.

Polarization effects

Ions in crystal lattices of purely ionic compounds are spherical; however, if the positive ion is small and/or highly charged, it will distort the electron cloud of the negative ion, an effect summarised in Fajans' rules. This polarization of the negative ion leads to a build-up of extra charge density between the two nuclei, i.e., to partial covalency. Larger negative ions are more easily polarized, but the effect is usually only important when positive ions with charges of 3+ (e.g., Al3+) are involved. However, 2+ ions (Be2+) or even 1+ (Li+) show some polarizing power because their sizes are so small (e.g., LiI is ionic but has some covalent bonding present). Note that this is not the ionic polarization effect which refers to displacement of ions in the lattice due to the application of an electric field.

Ionic versus covalent bonds

In an ionic bond, the atoms are bound by attraction of opposite ions, whereas, in a covalent bond, atoms are bound by sharing electrons. In covalent bonding, the molecular geometry around each atom is determined by VSEPR rules, whereas, in ionic materials, the geometry follows maximum packing rules.

In reality, purely ionic bonds do no


From Yahoo Answers

Question:They say (maybe..) molecule is the smallest compound or what, what is the difference between them? And what about chemical bond, is that also the same? Sry, i've been always bad at chemistry, simple answers. I really need to finish my graphic designing degree and i need to pass this chemistry class..

Answers:a molecule is the smallest unit of an element or a compound that is capable of independent existence. a compound is a substance that is made up of the same type of element bonded together in a fixed ratio. a chemical bond can be of two types - covalent and elctrovalent. in a covalent bond a molecule is formed by sharing of electrons between element. in an electrovalent bond the molecule is formed by the interionic orces bteween the elements.

Question:1.Write a paragraph to explain why is it incorrect to talk of molecules of sodium chloride, but correct to talk of molecules of ammonia. 1.Write a paragraph to explain why an ionic bond is also called electrovalent. 2.What are the characteristics of Lewis acids? 2.What is an alkali? Give examples of its properties. 3.Explain why copper is a good conductor of electricity, but it is a non-electrolyte. 3.Explain why a solution of the ionic compound is an electrolyte while the covalent compound is non-electrolyte. 4.Explain what is meant by actinide series. Use the space provided below to type your answer. 4.State one reason for keeping chlorine and bromine in the same group of the periodic table. 5. Explain what is meant by the term solubility. 5.What are the uses of solubility curves? Each question should be a paragraph long! I know its a lot, but I need help so bad, I've look everywhere on the internet! Please e-mail me answers at Temanaha16@yahoo

Answers:if you have a chemistry book that might help.

Question:1. describe the difference between ionic and covalent bonds? 2. whats the difference between polar covalent bond and non-polar covalent bond? 3.classify the following as polar or non-polar covalent bonds-H2, O2, HCl, CCl4, Br2, HI, H20 4. whats the difference between organic and inorganic compunds 5. name some examples of organic compounds classify the following as ionic or covalent compounds-NaCl, HCl, N2, CaCl2, H2O, O2

Answers:1. An ionic bond (or electrovalent bond) is a type of chemical bond that can often form between metal and non-metal ions (or polyatomic ions such as ammonium) through electrostatic attraction. In short, it is a bond formed by the attraction between two oppositely charged ions. A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, or between atoms and other covalent bonds. In short, attraction-to-repulsion stability that forms between atoms when they share electrons is known as covalent bonding. 2.in polar covalent bonds the bonding atoms have difference in their electonegativity(i.e. the tendency to pull the shared pair of electrons towards themselves), thus they get a small negative(for more electronegative element) and a small positice charge(for less electronegative). in non-polar covalent bonds the bonded atoms have the same electronegativity, like H2 and thus both are neutral. 3. Polar- HCl, CCl4, HI, H2O Non Polar- H2, O2,Br2 4. a compound having carbon and hydrogen and its derivative is called an organic compound while a compound which is mineral based and not biologial based is an inorganic compound. 5. organic compounds- formaldehyde, phenol, acetic acid phew! tht was lot of typing, i deserve a best answer

Question:Science wise.

Answers:Chemical Bonding Chemical compounds are formed by the joining of two or more atoms. A stable compound occurs when the total energy of the combination has lower energy than the separated atoms. The bound state implies a net attractive force between the atoms ... a chemical bond. The two extreme cases of chemical bonds are: Covalent bond: bond in which one or more pairs of electrons are shared by two atoms. Ionic bond: bond in which one or more electrons from one atom are removed and attached to another atom, resulting in positive and negative ions which attract each other. Other types of bonds include metallic bonds and hydrogen bonding. The attractive forces between molecules in a liquid can be characterized as van der Waals bonds. -x-x-x-x-x-x IONIC BOND: are forces that hold ionic compounds together If a negative ion meets a positive one, their opposite charges attract strongly and glue the atoms together. This type of gluing is called an ionic bond. Ionic bonds were first formed as atoms emerged from a supernova, and caused cosmic dust grains to form. They are important in holding the atoms together in many rocks on the Earth today. An ionic bond is sometimes called an electrovalent bond. COVALENT BOND: this major type of bond holds atoms together - A covalent bond is formed when the electron clouds of two atoms overlap. Where the clouds overlap they are thicker, and their electric charge is stronger. Both nuclei feel a force of attraction towards this thick electron cloud, and so the two atoms are held together. A group of atoms joined in this way is known as a molecule. The number of covalent bonds which an atom can form depends on how many electrons it has. The shell model explains this. METALLIC BOND: The properties of metals suggest that their atoms possess strong bonds, yet the ease of conduction of heat and electricity suggest that electrons can move freely in all directions in a metal. The general observations give rise to a picture of "positive ions in a sea of electrons" to describe metallic bonding.