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:Ionic bonds: Transfer of electronsTransfer of electrons Involves a metal and a nonmetalInvolves a metal and a nonmetal Covalent bonds:Covalent bonds: Sharing of electronsSharing of electrons Involves two nonmetalsInvolves 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

Ionic Bonding Let’s see how sodium (Na) bonds with chlorine (Cl) Chlorine now has an octet (8 valence electrons) and sodium does too Na Metal Cl Nonmetal After donating/ accepting electrons, these atoms are now bonded together ClNa + New Compound

Covalent Bonding Bond between two nonmetals 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

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. These are the shared electrons F Nonmetal F + FF After sharing, these atoms are now bonded together

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.