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BONDING. Bonds Between Atoms. Ionic. Covalent. Network Solids. Molecular Substance. Ionic Bonds. What is an Ionic Bond ?. - An Ionic Bond is a chemical bond resulting from the TRANSFER of electrons from one bonding atom to another. When is an ionic bond formed?.
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Bonds Between Atoms Ionic Covalent Network Solids Molecular Substance
Ionic Bonds • What is an Ionic Bond? • - An Ionic Bond is a chemical bond resulting from the TRANSFER of electrons from one bonding atom to another • When is an ionic bond formed? - An ionic bond is formed when a cation (positive ion) transfers electrons to an anion (negative ion).
Example 1 www.mhhe.com/physsci/chemistry/animations/chang_7e_esp/bom1s2_11.swf -
Example 2 • Some atoms, such as oxygen, need to gain two electrons to achieve stability. • The two electrons released by one magnesium atom could be gained by a single atom of oxygen. • When this happens, magnesium oxide (MgO) is formed.
Potassium Oxide • Click for Animation
Covalent Bonds • What is an Covalent Bond? • - A covalent bond is a chemical bond resulting from SHARING of electrons between 2 bonding atoms. • What forms a covalent bond? - A covalent bond is formed between two nonmetals. Click for animation
Examples of Covalent molecules • The neutral particle is formed when atoms share electrons is called a molecule • A molecule is the basic unit of a molecular compound.
What are some characteristics of an ionic bond? • Crystalline at room temperatures • Have higher melting points and boiling points compared to covalent compounds • Conduct electrical current in molten or solution state but not in the solid state
What are some characteristics of a covalent bond? • Covalent bonds have definite and predicable shapes. • Very strong • Low melting and boiling points
Covalent Bonds can have multiple bonds, so you should be familiar with the following… Single Covalent Bond- chemical bond resulting from sharing of an electron pair between two atoms. Double Covalent Bond- chemical bond resulting from sharing of two electron pairs between two atoms. Triple Covalent Bond-chemical bond resulting from sharing of three electron pairs between two atoms.
Covalent Network Structures • A covalent network is when atoms are bonded together covalently to form giant macromolecular structures. • The element Carbon can form Covalent Network structures • Two examples are: Diamond & Graphite
Diamond • Each Carbon atom bonds to 4 others • Strong covalent bonds throughout • High melting points and Boiling points • No free electrons so does not conduct electricity.
Graphite • Each Carbon atom is bonded to 3 others • The bonding within the layers is strong covalent. • The spare fourth electron of each C atom is delocalised so graphite can conduct electricity • There are weak intermolecular forces of attraction between the layers.
Covalent Networks • Another example of a covalent network is silicon dioxide. This is a compound though it resembles diamond.