Question 1

Which of the following statements best describes a valence electron?

Accepted Answer

A valence electron is an electron found in the highest principal energy level of an atom.

Question 2

According to the octet rule, atoms tend to gain, lose, or share electrons in order to:

Accepted Answer

Achieve the electron configuration of a noble gas, usually 8 valence electrons.

Question 3

Which of the following elements has 5 valence electrons?

Accepted Answer

Nitrogen (N)

Question 4

What is the correct Lewis dot symbol for a chloride ion (Cl⁻)?

Accepted Answer

$$ [\cdot \cdot \cdot \cdot \mathrm{Cl} \cdot \cdot \cdot \cdot]^{-} $$

Question 5

Which of the following compounds is ionic?

Accepted Answer

NaCl

Question 6

A molecule of CO$$_2 is $$nonpolar because:

Accepted Answer

It has polar bonds, but the molecule is linear and symmetrical, so the dipoles cancel.

Question 7

Which of the following best describes the difference between ionic and covalent bonds?

Accepted Answer

Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.

Question 8

Which of the following pairs of elements is most likely to form a polar covalent bond?

Accepted Answer

H and O

Question 9

What is the molecular geometry and bond angle of methane (CH$$_4$$)?

Accepted Answer

Tetrahedral, 109.5°

Question 10

Which of the following statements about electronegativity is correct?

Accepted Answer

Electronegativity decreases down a group and increases across a period.

Question 11

A molecule of ammonia (NH$$_3) is $$polar because:

Accepted Answer

It has polar bonds and a trigonal pyramidal shape, resulting in a net dipole moment.

Question 12

Which of the following is the correct Lewis structure for carbon dioxide (CO$$_2$$)?

Accepted Answer

$$ \mathrm{O} = \mathrm{C} = \mathrm{O} $$

Question 13

Which of the following best explains why oil and water do not mix?

Accepted Answer

Oil is nonpolar and water is polar, so they are not attracted to each other.

Question 14

Which of the following molecules has a trigonal planar geometry?

Accepted Answer

BF$$_3$$

Question 15

What is the correct formula for the ionic compound formed between potassium (K) and oxygen (O)?

Accepted Answer

K$$_2O$$

Question 16

Which of the following is a resonance structure?

Accepted Answer

One of two or more valid Lewis structures that can be drawn for a molecule, differing only in the placement of electrons.

Question 17

Which of the following species is an example of a polyatomic ion?

Accepted Answer

NO$$_3^-$$

Question 18

A molecule with four electron groups around the central atom, two of which are lone pairs, will have which molecular geometry?

Accepted Answer

Bent (tetrahedral bent)

Question 19

Which of the following best describes the bond in a molecule of N$$_2$$?

Accepted Answer

A triple covalent bond

Question 20

Which of the following is the correct order of decreasing electronegativity for the elements Rb, Si, Cl, Ca, Ga?

Accepted Answer

Cl \u003e Si \u003e Ga \u003e Ca \u003e Rb

Chemical Bonding and Molecular Geometry: Study Notes for Introductory Chemistry

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