Explain how the octet rule is related to bond formation

Identify the location of metals and nonmetals on the periodic table.

Describe how ionic bonds are formed Discuss some important properties of ionic

compounds

According to the octet rule, in forming compounds, atoms tend to combine with other atoms so that they each have 8 valence electrons

Anions (negative ions) and cations (positive ions) have opposite charges.

They attract one another by electrostatic forces

The forces of attraction that bind these oppositely charged ions are called ionic bonds

Compounds that consist of groups of ions joined by electrostatic forces are called ionic compound

In any sample of an ionic compound, the total positive charges of the cations must equal the total negative charges of the anions

Consider the reaction between sodium and chlorine◦Sodium has a single valence electron that it

can easily lose◦Chlorine has seven valence electrons and

can easily gain one◦When sodium and chlorine react to form a

compound, the sodium atom gives up its valence electron and a chlorine ion accepts this electron

The chemical formula of sodium chloride (NaCl) represents a formula unit, or the lowest whole-number ratio of cations to anions in an ionic compound

An aluminum atom has 3 valence electrons while bromine has 7

Therefore, aluminum wants to lose its 3 electrons while bromine wants to gain one more electron

This means that when aluminum and bromine react, three bromine atoms combine with each aluminum atom (AlBr3)

Ionic compounds are always composed of one nonmetal and one metal◦Electrons transfer from a metal to a nonmetal

Where are metals located on the periodic table? What about nonmetals?◦Metals = left of the stairs except hydrogen◦Nonmetals = right of stairs and plus hydrogen

Elements never gain or lose more than 3 electrons as they form ionic compounds

At room temperature, most ionic compounds are solids because the forces between ions are very strong◦Ionic solids have a high melting point

When melted, ionic compounds can conduct electric current

Ionic solids are also hard and dissolve easily in water

What is electronegativity???◦The ability of an atom to attract

electrons to itself

CalciumBromineAluminumMagnesiumNitrogenTellurium