CHEMICAL BONDING

THE A'LEVEL VIEW OF IONIC BONDING Electrons are transferred from one atom to another resulting in the formation of positive and negative ions. The electrostatic attractions between the positive and negative ions hold the compound together. So what's new? At heart - nothing. What needs modifying is the view that there is something magic about noble gas structures. There are far more ions which don't have noble gas structures than there are which do. Some common ions which don't have noble gas structures You may have come across some of the following ions in a basic course like GCSE. They are all perfectly stable , but not one of them has a noble gas structure. Fe 3+ [Ar]3d 5 Cu 2+ [Ar]3d 9 Zn 2+ [Ar]3d 10 Ag + [Kr]4d 10 Pb 2+ [Xe]4f 14 5d 10 6s 2 Noble gases (apart from helium ) have an outer electronic structure ns 2 np 6 .

Some other examples of ionic bonding magnesium oxide Again, noble gas structures are formed, and the magnesium oxide is held together by very strong attractions between the ions. The ionic bonding is stronger than in sodium chloride because this time you have 2+ ions attracting 2- ions. The greater the charge, the greater the attraction. The formula of magnesium oxide is MgO. calcium chloride This time you need two chlorines to use up the two outer electrons in the calcium. The formula of calcium chloride is therefore CaCl 2 . potassium oxide Again, noble gas structures are formed. It takes two potassiums to supply the electrons the oxygen needs. The formula of potassium oxide is K 2 O.

Ionic bonding in sodium chloride Sodium (2,8,1) has 1 electron more than a stable noble gas structure (2,8). If it gave away that electron it would become more stable. Chlorine (2,8,7) has 1 electron short of a stable noble gas structure (2,8,8). If it could gain an electron from somewhere it too would become more stable. The answer is obvious . If a sodium atom gives an electron to a chlorine atom, both become more stable. The sodium has lost an electron, so it no longer has equal numbers of electrons and protons. Because it has one more proton than electron, it has a charge of 1+. If electrons are lost from an atom, positive ions are formed . Positive ions are sometimes called cations. The chlorine has gained an electron, so it now has one more electron than proton . It therefore has a charge of 1-. If electrons are gained by an atom, negative ions are formed. A negative ion is sometimes called an anion. The nature of the bond The sodiu...

                                                IONIC BONDING An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed due to the attraction between an atom that has lost one or more electron and an atom that has gained one or more electrons.

 Questions relating to Chemical bonding 1.Why atoms form bonds? 2.What is chemical Bonding?

A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electrostatic force of attraction between opposite charges, either between electrons and nuclei , or as the result of a dipole attraction. The strength of chemical bonds varies considerably; there are "strong bonds" such as covalent or ionic bonds and "weak bonds" such as dipole–dipole interactions , the London dispersion force and hydrogen bonding .