5: Chemical Bonds, Ionic Bonds and Ionic Compounds
-
- 5.1: Why Atoms Form Bonds
- A chemical bond is a force of attraction between atoms or ions. Bonds form when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom that may be involved in chemical interactions. Valence electrons are the basis of all chemical bonds.
-
- 5.3: Metallic Bonds
- The electrons in the outer energy levels of a metal are mobile and capable of drifting from one metal atom to another. This means that the metal is more properly viewed as an array of positive ions surrounded by a sea of mobile valence electrons. Electrons which are capable of moving freely throughout the empty orbitals of the metallic crystal are called delocalized electrons (see below). A metallic bond is the attraction of the stationary metal cations to the surrounding mobile electrons.
-
- 5.5: Octet Rule
- In 1904, Richard Abegg formulated what is now known as Abegg's rule, which states that the difference between the maximum positive and negative valences of an element is frequently eight. This rule was used later in 1916 when Gilbert N. Lewis formulated the "octet rule" in his cubical atom theory. The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell.
-
- 5.8: Covalent Lewis Structures- Electrons Shared
- Ionic bonding typically occurs when it is easy for one atom to lose one or more electrons and another atom to gain one or more electrons. However, some atoms won’t give up or gain electrons easily. Yet they still participate in compound formation. How? There is another mechanism for obtaining a complete valence shell: sharing electrons. When electrons are shared between two atoms, they make a bond called a covalent bond.
-
- 5.11: Formulas for Ionic Compounds
- We have already encountered some chemical formulas for simple ionic compounds. A chemical formula is a concise list of the elements in a compound and the ratios of these elements. To better understand what a chemical formula means, we must consider how an ionic compound is constructed from its ions.
Thumbnail:This image shows bond formation between Lithium and Fluorine by electron transfer. Lithium being a metal loses an electron and Fluorine being a non-metal accepts electron. This results in an ionic bond and forms a compound called Lithium fluoride. It's formula is LiF. (CC BY-SA 4.0; Dharmeshkumar Shah via Wikimedia )