Question 1

Which of the following best explains why the second ionization energy of sodium ($$\mathrm{Na}) is $$much higher than its first ionization energy?

Accepted Answer

The second electron is removed from a filled valence shell, which is energetically unfavorable.

Question 2

Which of the following compounds is most likely to be ionic based on the elements involved?

Accepted Answer

NaCl

Question 3

According to Coulomb's Law, which factor most strongly affects the energy of an ionic bond?

Accepted Answer

The magnitude of the charges and the distance between ions

Question 4

Which of the following is the correct formula for ammonium sulfate?

Accepted Answer

$$\mathrm{(NH_4$)_2SO_4}$$

Question 5

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 6

Which statement best describes the difference between a single, double, and triple bond in terms of bond energy and bond length?

Accepted Answer

Triple bonds have the highest bond energy and shortest bond length.

Question 7

Which molecule below is nonpolar despite having polar bonds?

Accepted Answer

CO$$_2$$

Question 8

What is the formal charge on the central atom in the Lewis structure of nitrate ion ($$\mathrm{NO_3$^-}$$)?

Accepted Answer

0

Question 9

Which of the following best describes the concept of resonance in ozone ($$\mathrm{O_3$}$$)?

Accepted Answer

Resonance allows electron density to be delocalized, enabling ozone to absorb UV-B radiation.

Question 10

Which of the following best explains why bond formation is an exothermic process?

Accepted Answer

Bond formation releases energy as atoms achieve lower potential energy.

Question 11

Given the molar mass of glucose ($$\mathrm{C_6H_{12}O_6$}) is$$ $$180\ \mathrm{g/mol}$$, how many moles are in $$90\ \mathrm{g} of $$glucose?

Accepted Answer

$$0.5\ \mathrm{mol}$$

Question 12

Which of the following best describes the shape and bond angles of ammonia ($$\mathrm{NH_3$}) $$according to VSEPR theory?

Accepted Answer

Trigonal pyramidal with bond angles slightly less than $$109.5^\circ$$

Question 13

Which of the following is the correct name for $$\mathrm{$$FeCl_3$$}$$?

Accepted Answer

Iron(III) chloride

Question 14

Which hybridization is found in the central carbon atom of ethene ($$\mathrm{C_2H_4}$$)?

Accepted Answer

$$\mathrm{sp^2$}$$

Question 15

Which of the following statements about sigma ($$\sigma) $$and pi ($$\pi) $$bonds is correct?

Accepted Answer

A double bond consists of one $$\sigma$$ bond and one $$\pi$$ bond.

Question 16

Which of the following best explains why $$\mathrm{H_2$} is $$stable but $$\mathrm{He_2$} is $$not, according to molecular orbital theory?

Accepted Answer

In $$\mathrm{H_2$}$$, the bonding molecular orbital is filled and the antibonding orbital is empty, while in $$\mathrm{He_2$}$$, both are filled, resulting in no net bond.

Question 17

Which of the following best describes the difference between cis- and trans- isomers?

Accepted Answer

Cis-isomers have substituents on the same side of a double bond, while trans-isomers have them on opposite sides.

Question 18

Which of the following is the correct formula for calcium phosphate?

Accepted Answer

$$\mathrm{Ca_3$(PO_4$)_2}$$

Question 19

A chemical reaction requires breaking the following bonds: 2 moles of $$\mathrm{H-H}$$ ($$436\ \mathrm{kJ/mol}) $$and 1 mole of $$\mathrm{O=O}$$ ($$498\ \mathrm{kJ/mol}). It $$forms 2 moles of $$\mathrm{O-H}$$ bonds ($$463\ \mathrm{kJ/mol}$$ each). What is the net energy change ($$\Delta H) $$for the reaction?

Accepted Answer

$$-285\ \mathrm{kJ}$$

Study Guide: Atomic Properties, Chemical Bonding, and Molecular Structure

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