Which bond transfers electrons

Ionic bonding Definition: An ionic bond is formed when valence electrons are transferred from one atom to the other to complete the outer electron shell. The sodium Na atom gives up its valence electron to complete the outer shell of the chlorine Cl atom. Ionic materials are generally very brittle, and strong forces exist between the two ions. Covalent bonding Definition: A covalent bond is formed when the valence electrons from one atom are shared between two or more particular atoms.

Example: Many compounds have covalent bonding, such as polymers. Some covalently bounded compounds have a small difference in charge along one direction of the molecule. This difference in charge is called a dipole, and when the covalent bond results in this difference in charge, the bond is called a polar covalent bond. These kinds of bonds occur when the shared electrons are not shared equally between atoms.

If one atom has a higher electronegativity, the electrons will be drawn closer to the nucleus of that atom, resulting in a small net charge around each nucleus of the atoms in the molecule. If the atoms in the molecule have the same electronegativity for example, if the atoms are the same, as in N 2 , then the shared electrons will not be drawn towards one nucleus more than another, and the bond will be nonpolar.

Similarly, the higher the difference in electronegativity, the more unequal the sharing of electrons is between the nuclei, and the higher the polarity of the bond. A given nonmetal atom can form a single, double, or triple bond with another nonmetal. Which type of bond is formed between the atoms depends on their numbers of valence electrons.

An electron transfers from the Na atom to the Cl atom:. Both species now have complete octets, and the electron shells are energetically stable. From basic physics, we know that opposite charges attract. The attraction between oppositely charged ions is called an ionic bond, and it is one of the main types of chemical bonds in chemistry. Ionic bonds are caused by electrons transferring from one atom to another. In electron transfer, the number of electrons lost must equal the number of electrons gained.

We saw this in the formation of NaCl. A similar process occurs between Mg atoms and O atoms, except in this case two electrons are transferred:.

The two ions each have octets as their valence shell, and the two oppositely charged particles attract, making an ionic bond:. Remember, in the final formula for the ionic compound, we do not write the charges on the ions. What about when an Na atom interacts with an O atom? The O atom needs two electrons to complete its valence octet, but the Na atom supplies only one electron:. The O atom still does not have an octet of electrons. What we need is a second Na atom to donate a second electron to the O atom:.

Most of these solids are soluble in H 2 O and conduct electricity when dissolved. The ability to conduct electricity in solution is why these substances are called electrolytes. Table salt, NaCl, is a good example of this type of compound. Ionic bonds differ from covalent bonds. Both types result in the stable electronic states associated with the noble gases. However, in covalent bonds, the electrons are shared between the two atoms. All ionic bonds have some covalent character, but the larger the difference in electronegativity between the two atoms, the greater the ionic character of the interaction.