An ionic bond is the force of attraction between the opposite charges of an ion. One element in an ionic bond loses electrons, and another element must gain the electrons. Some atoms lose electrons to make the outside energy levels become more stable. Atoms become more stable when their outer most energy level has 8 electrons. Pure ionic compounds usually are crystalline solids, liquids, or gases. Many ionic compounds are binary compounds.
This shows an atom losing an electron.
Ionic compounds usually have much higher melting and boiling points than covalent compounds.
Ionic Compounds:
Ionic Compounds:
Compound
Melting Point
NaCl
8010C
MgO
28520C
NaBr
7470C
LiF
840C
A covalent bond is formed when electrons are shared between atoms. Covalent bonds are between non-metals and non-metals or hydrogen and non-metals. They share electrons so that both of them can have a stable octet.
Metallic Bonding
Metals consist of a lattice of positive ions through which a cloud of electrons move. The electrons are the valency electrons of the metal, e.g. for sodium they are the outermost electron from each atom. The positive ions tend to repel one another, but are held together by the negatively charged electron cloud.
Because of this presence of mobile electrons, metals are able to conduct electricity
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