Ionic Bonding

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Slide 1

Ionic Bonding

Slide 2

CA Standards

Students know atoms combine to form molecules by sharing electrons to form covalent or metallic bonds or by exchanging electrons to form ionic bonds.

Students know salt crystals, such as NaCl, are repeating patterns of positive and negative ions held together by electrostatic attraction.

Slide 3

Bonds

Forces that hold groups of atoms

together and make them function

as a unit.

Ionic bonds – transfer of electrons

Covalent bonds – sharing of electrons

Slide 4

The Octet Rule – Ionic Compounds

Ionic compounds form so that each atom, by gaining or losing electrons, has an octet of electrons in its highest occupied energy level.

Metals lose electrons to form positively-charged cations

Nonmetals gains electrons to form negatively-charged anions

Slide 5

Ionic Bonding

The Formation of Sodium Chloride

Sodium has 1 valence electron

Cl: 1s22s22p63s23p5

Na: 1s22s22p63s1

Chlorine has 7 valence electrons

An electron transferred gives

each an octet

Slide 6

Ionic Bonding: The Formation of Sodium Chloride

Cl- 1s22s22p63s23p6

Na+ 1s22s22p6

This transfer forms ions, each with an octet:

Slide 7

Ionic Bonding: The Formation of Sodium Chloride

Cl-

Na+

The resulting ions come together due to electrostatic attraction

(opposites attract):

The net charge on the compound must equal zero

Slide 8

Examples of Ionic compounds

Mg2+Cl-2

Na+2O2-

Magnesium chloride: Magnesium loses two electrons and each chlorine gains one electron

Sodium oxide: Each sodium loses one electron and the oxygen gains two electrons

Al3+2S2-3

Aluminum sulfide: Each aluminum loses two electrons (six total) and each sulfur gains two electrons (six total)

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Sodium Chloride Crystal Lattice

Ionic compounds form solid crystals at ordinary temperatures.