find out how atoms or groups of atoms combine to form ionic compounds

5-2: Ionic BondsFind out how atoms or groups of atoms

combine to form ionic compounds.

Anticipatory Set

Electrons have a negative charge.

Overall, an atom is neutral in charge.

Positive & negative charges are attracted to each other.

Elements in group 1 have 1 valence electronand elements in group 17 have 7 valence electrons.

California StandardsScience Standard 8.3.b: Students know that compounds

are formed by combining two or more different elements and that compounds have properties that are different from their constituent elements.

Science Standard 8.3.c: Students know that atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers.

Reading Comprehension 8.2.7: (compare & contrast): Evaluate the unity, coherence, logic, internal consistency, and structural patterns of text.

InputIon: an atom or group of atoms that has an

electric charge.polyatomic ion: ions that are made of more

than one atom.ionic bond: the attraction between two

oppositely charged ions.ionic compound: a compound that consists

of positive and negative ions.

Inputchemical formula: a combination of symbols

that shows the ratio of elements in a compound.

subscript: tells you the ratio of elements in the compound.

crystal: an orderly, three-dimensional pattern of ions or atoms in a solid.

Input & ModelingIons

An ion is an atom or group of atoms that has an electric charge.

When an atom loses an electron it becomes a positive ion (has an extra proton).

When an atom gains an electron it becomes a negative ion (has an extra electron).

Look at figure 8 on page 185.How do ions form bonds?

Ionic bonds form as a result of the attraction between positive and negative ions.

InputIonic Compounds

Sodium has 1 valence electron

Chlorine has 7 valence electrons

http://web.jjay.cuny.edu/~acarpi/NSC/salt.htm

InputChemical Formulas and Names

When ionic compounds form, the ions come together in a way that balances out the charges on the ions. The chemical formula for the compound reflects this balance.

If the negative ion is a single element (NaCl – sodium chloride) the end of its name changes to –ide.

If the negative ion is polyatomic (NH4NO3 – ammonium nitrate) the end of the name is –ate or –ite.

For an ionic compound, the name of the positive ion comes first, followed by the name of the negative ion.

InputChemical Formulas and Names

A chemical formula is a combination of symbols that shows the ratio of elements in a compound.

A subscript tells you the ratio of elements in the compound.

InputProperties of Ionic Compounds

In general, ionic compounds are hard, brittle solids with high melting points.

When melted or dissolved in water, they conduct electric current.

How does an ion with a charge of 2+ form?

Check forUnderstanding

By losing 2 electrons

What is the name of the ionic compound N2S?

Potassium sulfide

InputStandard 8.2.7: Compare & Contrast

When you compare and contrast, you examine the similarities and differences among things. These not only tell you more about the two things but might point to a relationship between them.

Inputunity: refers to the way the ideas in a

piece of writing hang together.

coherence: the connection of ideas that makes them easy to follow.

Organization patterns:comparison and contrast: shows

similarities and differences

ModelingCompare & Contrast:

• You can compare and contrast by using a table.• List the items to be compared in the first column

and the characteristics to be compared across the top of the table.

Substance Color State at Room Temperature

Melting Point Reactivity

Table Salt/Sodium Chloride (NaCl)Sodium (Na)

Chlorine(Cl)

ModelingCompare & Contrast:

• You can compare and contrast by using a table.• List the items to be compared in the first column

and the characteristics to be compared across the top of the table.

Substance Color State at Room Temperature

Melting Point Reactivity

Table Salt/Sodium Chloride (NaCl)

White Solid 901 degrees Celsius

Nonreactive

Sodium (Na)

Silvery white

Solid 98 degrees Celsius

Reactive

Chlorine(Cl)

Greenish yellow

Gas -101 degrees Celsius

Nonreactive

ModelingCompare & Contrast:

• Compare and contrast the properties of Sodium Chloride (NaCl), Sodium (Na), and Chlorine (Cl).

• Both sodium chloride and sodium are solid at room temperature. Chlorine and sodium chloride are nonreactive. Sodium chloride retains neither the properties of Sodium nor the properties of chlorine. This is because compounds (such as sodium chloride) have their own characteristics, and not the characteristics of its component elements.

ModelingCompare & Contrast:

• Read the information in Figure 9 on page 186. Compare and contrast a Sodium Ion and a Chloride Ion.• Both sodium and chlorine are looking to become

more stable by gaining or loosing valence electrons. When this happens, both become ions. Sodium looses one electron and chlorine gains one election. The sodium ion has a positive charge, but the chloride ion has a negative charge.

Answer the Practice Question

Guided Practice

Independent PracticeFinish the worksheet & go on to the Extension

EXTENSION & HOMEWORK Write a detailed SUMMARY of the section and

complete the UNANSWERED QUESTIONS section of your notes.

Choose two of the remaining Depth & Complexity ICONS in your notes and explain how they relate to this section.

Complete the 5.2 Ionic Bond Reading Comprehension worksheet & Review and Reinforce worksheet.