$$\text{Formal Charge} = \text{number of valence electrons} - (\text{number of lone-pair electrons} + \text{number of bonds})$$

Question 1

Which statement best explains why carbon is central to organic chemistry?

Accepted Answer

Carbon shares electrons, allowing it to form stable covalent bonds with many elements.

Question 2

What is the formal charge on the oxygen atom in a hydroxide ion ($$\mathrm{OH^-}$$)?

Accepted Answer

$$-1$$

Question 3

Which of the following molecules has a nonpolar covalent bond?

Accepted Answer

$$\mathrm{H_2$}$$

Question 4

Given the electronic configuration of carbon ($$1s^2$$ $$2s^2$$ $$2p^2$$), how many valence electrons does a neutral carbon atom have?

Accepted Answer

4

Question 5

Which principle states that electrons fill the lowest energy orbitals first?

Accepted Answer

Aufbau principle

Question 6

What is the bond angle in a molecule where the central atom is $$sp^3$$ hybridized?

Accepted Answer

$$109.5^\circ$$

Question 7

Which of the following best describes the difference between an ionic and a covalent bond?

Accepted Answer

Ionic bonds involve the attraction of opposite charges, while covalent bonds involve sharing electrons.

Question 8

Which molecule would have the largest dipole moment based on the data provided?

Accepted Answer

$$\mathrm{H-F}$$

Question 9

A nitrogen atom in ammonia ($$\mathrm{NH_3$}) $$forms three bonds and has one lone pair. What is the expected bond angle?

Accepted Answer

$$107.3^\circ$$

Question 10

Which of the following is the correct condensed structure for ethane?

Accepted Answer

$$\mathrm{CH_3CH_3}$$

Question 11

If a carbon atom forms only three bonds, what is the resulting species called?

Accepted Answer

Carbocation

Question 12

Which of the following statements about atomic orbitals is correct?

Accepted Answer

Within a shell, $$s$$ orbitals have lower energy than $$p$$ orbitals.

Question 13

What is the formal charge on nitrogen in the ammonium ion ($$\mathrm{NH_4$^+}$$)?

Accepted Answer

$$+1$$

Question 14

Which of the following best describes the bond in ethyne ($$\mathrm{C_2H_2}$$)?

Accepted Answer

Each carbon forms two $$sp$$ hybridized bonds and two $$p$$ bonds.

Question 15

Which of the following is true regarding the relationship between bond length and bond strength?

Accepted Answer

The shorter the bond, the stronger it is.

Question 16

What is the total number of valence electrons in the nitrate ion ($$\mathrm{NO_3$^-}$$)?

Accepted Answer

24

Question 17

Which of the following best describes the geometry of methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

Tetrahedral

Question 18

Which rule states that electrons occupy empty degenerate orbitals before pairing up?

Accepted Answer

Hund's rule

Question 19

Which of the following molecules would you expect to have the smallest bond angle?

Accepted Answer

$$\mathrm{H_2O}$$

Question 20

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

Accepted Answer

$$	ext{Formal Charge} = 	ext{number of valence electrons} - (	ext{number of lone-pair electrons} + 	ext{number of bonds})$$

Chapter 1: Remembering General Chemistry – Electronic Structure and Bonding

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