Question 1

Which statement best explains why ionic compounds like NaCl have high melting points?

Accepted Answer

Because the ions are held together by strong electrostatic forces between oppositely charged ions, requiring a large amount of energy to break.

Question 2

Given the formula unit MgF$$_2$$, what are the charges on the magnesium and fluoride ions, respectively?

Accepted Answer

Mg$$^{2+}$$ and F$$^{-}$$

Question 3

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to achieve the electron configuration of a noble gas, usually having 8 valence electrons.

Question 4

What is the correct chemical formula for a compound formed between aluminum (Al$$^{3+}) $$and phosphate (PO$$_4$$^{3-}$$) ions?

Accepted Answer

$$\mathrm{$$AlPO_4$$}$$

Question 5

Which of the following compounds will have the highest lattice energy?

Accepted Answer

$$\mathrm{MgO}$$

Question 6

What is the correct name for the molecular compound CO$$_2$$?

Accepted Answer

Carbon dioxide

Question 7

Which of the following is a diatomic molecule?

Accepted Answer

$$\mathrm{O_2$}$$

Question 8

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by sharing electrons between two nonmetal atoms.

Question 9

What is the correct Lewis dot structure for the sulfate ion, SO$$_4$$^{2-}$$, in terms of total valence electrons?

Accepted Answer

Sulfur has 6 valence electrons, each oxygen has 6, plus 2 for the charge: $$6 + 4 	imes 6 + 2 = 32$$ electrons.

Question 10

Which intermolecular force is present in all molecules, including nonpolar ones?

Accepted Answer

London dispersion forces (van der Waals)

Question 11

What is the correct formula for the ionic compound formed between calcium (Ca$$^{2+}) $$and nitrate (NO$$_3^-) $$ions?

Accepted Answer

$$\mathrm{Ca(NO_3$)_2}$$

Question 12

Which of the following molecules is polar?

Accepted Answer

$$\mathrm{H_2O}$$

Question 13

Which property is NOT typical of molecular compounds?

Accepted Answer

High electrical conductivity in solid state

Question 14

What is the formal charge on the central atom in the Lewis structure of NO$$_3^- ($$nitrate ion) if all atoms have an octet?

Accepted Answer

Nitrogen has a formal charge of $$+1$$

Question 15

Which of the following best describes the difference between a monoatomic and a polyatomic ion?

Accepted Answer

A monoatomic ion is formed from one element, while a polyatomic ion is formed from two or more elements.

Question 16

Which of the following is the correct name for the ionic compound Na$$_2SO$_4$$?

Accepted Answer

Sodium sulfate

Question 17

Which statement about the formation of MgO is correct?

Accepted Answer

Magnesium loses two electrons to form Mg$$^{2+}$$, and oxygen gains two electrons to form O$$^{2-}.$$

Question 18

Which of the following is the correct formula for the compound formed between potassium (K$$^+) $$and phosphate (PO$$_4$$^{3-}$$)?

Accepted Answer

$$\mathrm{K_3PO_4}$$

Question 19

Which of the following is a correct statement about the arrangement of ions in a crystal lattice?

Accepted Answer

Each ion is surrounded by oppositely charged ions, maximizing electrostatic attraction.

Question 20

Which of the following is the correct formula for the ionic compound formed between lithium (Li$$^+) $$and bromide (Br$$^-$$)?

Accepted Answer

$$\mathrm{LiBr}$$

Chemical Bonding: Ionic and Covalent Bonds, Electron Dot Structures, and Lattice Energy

Guida di studio - Domande di pratica