$$\text{Formal Charge} = \text{Valence Electrons} - (\text{Nonbonding Electrons} + \text{Bonding Electrons}/2)$$

Question 1

Which of the following is the correct ground state electron configuration for phosphorus (Z = 15)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^3$$

Question 2

Based on the periodic trend shown in the electronegativity diagram, which element is the most electronegative in Group 7A?

Accepted Answer

F

Question 3

How many octet electrons does the oxygen atom possess in methanol (CH$$_3OH$$)?

Accepted Answer

8 octet electrons: 6 valence and 2 shared electrons

Question 4

Which of the following is the correct formula for calculating the formal charge of an atom?

Accepted Answer

$$	ext{Formal Charge} = 	ext{Valence Electrons} - (	ext{Nonbonding Electrons} + 	ext{Bonding Electrons}/2)$$

Question 5

Given the thiocyanate ion (NCS$$^-$$), what is the formal charge on the nitrogen atom?

Accepted Answer

$$5 - (2 + 4/2) = 1$$

Question 6

Which statement about resonance structures is correct?

Accepted Answer

Only electrons from pi bonds or lone pairs move between resonance structures.

Question 7

What is the hybridization and number of unhybridized orbitals on the central carbon atom in HCN?

Accepted Answer

sp, 2 unhybridized p orbitals

Question 8

Which of the following molecules is nonpolar based on its molecular geometry?

Accepted Answer

CO$$_2$$

Question 9

Which functional group is present in both acetylcholine and choline, as shown in the acetylcholinesterase reaction?

Accepted Answer

Amine

Question 10

Which of the following best describes a hydrocarbon?

Accepted Answer

A molecule containing only carbon and hydrogen

Question 11

Which isotope of hydrogen contains one proton and two neutrons?

Accepted Answer

Tritium

Question 12

Which principle states that electrons fill orbitals of equal energy with the same spin before pairing up?

Accepted Answer

Hund's Rule

Question 13

Which of the following bonds is the shortest?

Accepted Answer

Triple bond

Question 14

What is the degree of unsaturation (IHD) for a molecule with the formula C$$_6H$_6$$?

Accepted Answer

$$(2 	imes 6 + 2 - 6)/2 = 4$$

Question 15

Which of the following statements about constitutional isomers is correct?

Accepted Answer

They have the same molecular formula but different connectivity.

Question 16

Which of the following best describes the resonance hybrid of the nitrate ion (NO$$_3^-$$)?

Accepted Answer

A composite structure showing delocalized electrons over all three oxygen atoms

Question 17

What is the hybridization of the central atom in a molecule with trigonal planar geometry?

Accepted Answer

sp$$^2$$

Question 18

Which of the following statements about molecular polarity is correct?

Accepted Answer

A molecule with a perfect shape and identical surrounding atoms is nonpolar.

Question 19

Which of the following best describes the difference between sigma ($$\sigma) $$and pi ($$\pi) $$bonds?

Accepted Answer

$$\sigma$$ bonds result from head-on overlap of orbitals, while $$\pi$$ bonds result from side-on overlap.

A Review of General Chemistry: Foundations for Organic Chemistry

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