Formal charge is calculated by $$\text{valence electrons} - (\text{nonbonding electrons} + \frac{1}{2}\text{bonding electrons}).$$

Question 1

Which element has the largest atomic radius among the following: Na, Mg, K, Ca? Explain using periodic trends.

Accepted Answer

K, because atomic radius increases down a group and decreases across a period.

Question 2

Which of the following ions has the smallest radius: $$\mathrm{Na^+}$$, $$\mathrm{Mg$$^{2+}$$}$$, $$\mathrm{K^+}$$, $$\mathrm{Ca$$^{2+}$$}$$?

Accepted Answer

$$\mathrm{Mg$$^{2+}$$}$$, because it has the highest charge and smallest electron cloud.

Question 3

Which element has the highest first ionization energy: Li, Na, K, Rb?

Accepted Answer

Li, because ionization energy decreases down a group.

Question 4

Which of the following pairs will form a neutral compound with the formula $$\mathrm{$$CaCl_2$$}$$?

Accepted Answer

$$\mathrm{Ca$$^{2+}$$}$$ and $$\mathrm{Cl^-}$$

Question 5

What is the correct Lewis structure for $$\mathrm{$$XeF_4$$}$$?

Accepted Answer

Xe with four single bonds to F and two lone pairs on Xe.

Question 6

Which compound is formed from $$\mathrm{Al$$^{3+}$$}$$ and $$\mathrm{NO_3$^-}$$?

Accepted Answer

$$\mathrm{Al(NO_3$)_3}$$

Question 7

Which of the following is the correct name for $$\mathrm{$$HClO_3$$}$$?

Accepted Answer

Chloric acid

Question 8

What is the correct formula for nitric acid?

Accepted Answer

$$\mathrm{$$HNO_3$$}$$

Question 9

Which of the following Lewis structures best represents $$\mathrm{NO_3$^-}$$, considering resonance?

Accepted Answer

One double bond and two single bonds, with negative charge on one oxygen.

Question 10

Which of the following is the most likely resonance form for $$\mathrm{HCNOF}$$, based on formal charges?

Accepted Answer

The structure with formal charges placed on the most electronegative atom.

Question 11

Which of the following statements about formal charge is correct?

Accepted Answer

Formal charge is calculated by $$	ext{valence electrons} - (	ext{nonbonding electrons} + \frac{1}{2}	ext{bonding electrons}).$$

Question 12

Which of the following acids is correctly matched with its anion?

Accepted Answer

Nitric acid and nitrate

Question 13

Which of the following is the correct formula for the compound formed from $$\mathrm{Ba$$^{2+}$$}$$ and $$\mathrm{NO_3$^-}$$?

Accepted Answer

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

Question 14

Which of the following best describes the bond lengths in the resonance structure of $$\mathrm{NO_3$^-}$$?

Accepted Answer

All N-O bonds are of equal length due to resonance.

Question 15

Which of the following is the correct Lewis structure for $$\mathrm{CO_2$}$$?

Accepted Answer

O=C=O with two lone pairs on each oxygen.

Question 16

Which of the following is the correct formula for the compound formed from $$\mathrm{Na^+}$$ and $$\mathrm{SO_4$^{2-}}$$?

Accepted Answer

$$\mathrm{Na_2SO_4}$$

Question 17

Which of the following is the correct name for $$\mathrm{$$HClO_2$$}$$?

Accepted Answer

Chlorous acid

Question 18

Which of the following is the correct formula for the compound formed from $$\mathrm{Mg$$^{2+}$$}$$ and $$\mathrm{Cl^-}$$?

Accepted Answer

$$\mathrm{$$MgCl_2$$}$$

General Chemistry Study Guidance: Atomic Radius, Electron Configurations, Lewis Structures, and Acids/Bases

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