Question

choose the best answer for each.

1. which of the following is true about ionic compounds?

a) they have low melting points
b) they conduct electricity as solids
c) they are formed between metals and nonmetals
d) they are usually gases at room temperature

1. when dissolved in water, ionic compounds:

a) stop conducting electricity
b) break apart into ions
c) form covalent bonds
d) evaporate quickly

1. ionic compounds generally have high melting and boiling points because:

a) they contain weak forces between molecules
b) they have strong electrostatic attractions between ions
c) they have delocalized electrons
d) their atoms share electrons equally

1. ionic compounds are generally solid at room temperature because:

a) they contain delocalized electrons
b) they have strong electrostatic forces between ions
c) they have weak dispersion forces
d) they are made of neutral molecules
part 4: true/false - ionic or covalent?
write true if the compound formed is ionic, and false if it is covalent.

1. sodium and oxygen →
2. nitrogen and hydrogen →
3. aluminum and chlorine →

Explanation:

• Question 8: Ionic compounds are formed between metals (which lose electrons to form cations) and non - metals (which gain electrons to form anions). They have high melting points (due to strong ionic bonds), do not conduct electricity as solids (ions are fixed in the lattice), and are usually solids at room temperature.
• Question 10: When ionic compounds dissolve in water, the polar water molecules break the ionic bonds, and the compound dissociates (breaks apart) into its constituent ions. These ions can then conduct electricity.
• Question 11: The strong electrostatic attractions (ionic bonds) between cations and anions in an ionic lattice require a large amount of energy to overcome, resulting in high melting and boiling points.
• Question 12: The strong electrostatic forces (ionic bonds) between ions in an ionic lattice hold the ions in a fixed, ordered arrangement, making ionic compounds generally solid at room temperature.
• Question 13: Sodium (a metal) and oxygen (a non - metal) form an ionic compound (sodium oxide, \(Na_2O\)).
• Question 14: Nitrogen and hydrogen (both non - metals) share electrons to form covalent bonds (ammonia, \(NH_3\)).
• Question 15: Aluminum (a metal) and chlorine (a non - metal) form an ionic compound (aluminum chloride, \(AlCl_3\)).

Answer:

1. C. They are formed between metals and nonmetals
2. B. Break apart into ions
3. B. They have strong electrostatic attractions between ions
4. B. They have strong electrostatic forces between ions
5. True
6. False
7. True