2a. Properties of Ionic and Covalent Compounds

Galen lists the properties of four covalent compounds and two ionic compounds in the table below. If his teacher asks him about a different covalent compound, what can he predict about its properties? Select all that apply.

• It consists of all metals.

• It consists of all nonmetals.

• It has a high boiling point.

• It has a low boiling point.

• It consists of nonmetals and metals.

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NGSS.MS-PS1-1

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The following table summarizes melting points for different types of compounds. 

How does the type of compound relate to its melting point?

• The melting points of ionic and covalent compounds show no relationship.

• The melting points for ionic compounds are lower than for covalent compounds.

• The melting points for ionic compounds are higher than for covalent compounds.

• The melting points for ionic compounds are equal to those for covalent compounds.

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NGSS.MS-PS1-2

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Bonnie tests an unknown compound and discovers that it has these properties: high melting point, high boiling point, and conductivity when melted. Which compounds could be the unknown compound: NH3, HCl, or NaCl?

• NH₃

• HCl

• NaCl

• H₂O

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NGSS.MS-PS1-4

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Dan tests the conductivity of solid NaCl, melted NaCl, and NaCl dissolved in water. His observations are in the table below. NaCl is an ionic compound. How could Dan correctly describe the conductivity of ionic compounds using his observations? Select all that apply.

• All ionic compounds conduct electricity.

• Ionic compounds do not conduct electricity.

• Melted ionic compounds conduct electricity.

• Solid ionic compounds do not conduct electricity.

• Melted ionic compounds do not conduct electricity.

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Jane studies the properties of four ionic compounds: NaCl, KBr, CaS, and MgO, as shown in the table. What can she conclude about the elemental compositions of ionic compounds?

• They contain semimetallic and metallic elements.

• They contain metallic and transition elements.

• They contain metallic and nonmetallic elements.

• They contain semimetallic and nonmetallic elements.

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NGSS.MS-PS1-1