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Investigative Science. 12/2/11 Ionic and Covalent Bonding. 2 Types of Bonds. Forces that hold groups of atoms together and make them function as a compound. Ionic bonds: Transfer of electrons Involves a metal and a nonmetal Covalent bonds: Sharing of electrons Involves two nonmetals.
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Investigative Science 12/2/11 Ionic and Covalent Bonding
2 Types of Bonds • Forces that hold groups of atoms together and make them function as a compound. • Ionic bonds: • Transfer of electrons • Involves a metal and a nonmetal • Covalent bonds: • Sharing of electrons • Involves two nonmetals
Metals • Metals: • Located on the left-hand side of the periodic table to underneath the staircase on the right-hand side
Nonmetals • Nonmetals: • Located above the staircase on the right-hand side
Metalloids • Metalloids: • Located along the staircase. • Have properties of both metals and nonmetals
The Octet Rule • Each type of bond requires that both atoms involved in the reaction fulfill an octet, or have 8 valence electrons. • Ionic: • One element donates its valence electrons (the metal), the other accepts those valence electrons (the nonmetal). Both fulfill the octet rule by donating/accepting valence electrons. • Covalent: • Both elements share their valence electrons to fulfill the octet rule. Both elements are nonmetals.
Ionic Bonding • A metal donates its electron(s) to a nonmetal element • Metals have less electrons in their valence shell and can donate their electrons. It is easier for them to give them away than attract more valence electrons for an octet • By donating its electron(s) to the nonmetal, the metal and nonmetal become bonded together to form a new compound. • This type of reaction can be shown by using Lewis Dot Structures
Na Cl Na Cl After donating/ accepting electrons, these atoms are now bonded together Metal Nonmetal Ionic Bonding • Let’s see how sodium (Na) bonds with chlorine (Cl) • Chlorine now has an octet (8 valence electrons) and sodium does too + New Compound
Covalent Bonding • Bond between twononmetals • Because both elements still need an octet, they are forced to share electrons because they have too many valence electrons and can’t donate any • It is not easy for one element to give up its electrons like a metal, which has less electrons in its valence shell • Hydrogen also bonds as a nonmetal, but does not need eight valence electrons. It only needs 2, called a DUET. • Lewis Dot Structures can also show this bond
F F F F + After sharing, these atoms are now bonded together Nonmetal Nonmetal These are the shared electrons Covalent Bonding • Let’s see how fluorine (F) bonds with itself • Each fluorine atom has 7 valence electrons. They EACH need one more valence electron to fulfill the octet rule, so they will each SHARE one electron with each other.
Let’s Practice! • Show how an ionic bond forms between Magnesium and Oxygen. • Show how an ionic bond forms between Sodium and Fluorine. • Show how a covalent bond forms between Hydrogen and Oxygen.