Electronegativity and Chemical Bonds

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Which of the following elements has the highest electronegativity?

Francium
Fluorine (correct)
Cesium
Lithium

How does electronegativity change as you move down a group (vertical column) on the periodic table for representative elements?

Electronegativity increases, then decreases.
Electronegativity remains constant.
Electronegativity generally increases.
Electronegativity generally decreases. (correct)

How does electronegativity change as you move across a period (horizontal row) on the periodic table for representative elements?

Electronegativity generally increases. (correct)
Electronegativity decreases, then increases.
Electronegativity remains constant.
Electronegativity generally decreases.

In a chemical bond between hydrogen (H) and oxygen (O), which atom will have a greater attraction for the shared electrons?

Oxygen, because it has a higher electronegativity. (A) Signup and view all the answers

The polarity of a chemical bond is determined by:

The difference between the electronegativity values of the atoms forming the bond. (C) Signup and view all the answers

If element X has an electronegativity of 0.9 and element Y has an electronegativity of 3.5, what type of bond is most likely to form between them?

Ionic bond (B) Signup and view all the answers

Which of the following bonds would be considered the MOST polar?

F-H (Fluorine-Hydrogen) (B) Signup and view all the answers

Element A has an electronegativity of 3.0, and Element B has an electronegativity of 3.0. What type of bond will they form?

Nonpolar Covalent Bond. (A) Signup and view all the answers

Considering electronegativity differences, which of the following correctly ranks the bonds in order of decreasing polarity (most polar to least polar)?

C–F, N–F, O–F (C) Signup and view all the answers

Based on electronegativity trends, which sequence lists bonds from most to least polar?

Si–F, C–F, N–O (C) Signup and view all the answers

Considering electronegativity, arrange the following bonds in order from most polar to least polar: Cl–Cl, B–Cl, S–Cl.

B–Cl, S–Cl, Cl–Cl (A) Signup and view all the answers

Which of the following bonds is the least polar while still being considered a polar covalent bond?

N–O (B) Signup and view all the answers

Which of the following bonds would be the most polar without being considered ionic?

Si–O (D) Signup and view all the answers

A molecule has a measurable dipole moment. Which statement best describes this molecule?

It has distinct centers of positive and negative charge. (B) Signup and view all the answers

In a molecule with a dipole moment, what does the arrow representing the dipole indicate?

It points from the positive charge center to the negative charge center. (A) Signup and view all the answers

Water ($H_2O$) is a polar molecule. What is the primary reason for this polarity?

The bent molecular geometry and the difference in electronegativity between oxygen and hydrogen. (A) Signup and view all the answers

Why does the polarity of water significantly affect its properties?

It allows water to dissolve ionic compounds and remain a liquid at typical Earth surface temperatures. (A) Signup and view all the answers

An element from Group 6 forms an ion. What charge would you expect this ion to have?

2- (A) Signup and view all the answers

Which statement accurately describes how metals achieve a noble gas electron configuration to form stable compounds?

Metals lose electrons. (C) Signup and view all the answers

How do nonmetals achieve a noble gas electron configuration to form stable compounds?

By gaining electrons. (C) Signup and view all the answers

In a crystal of lithium fluoride (LiF), how are the ions arranged to maximize attraction?

Li+ and F- ions are packed together, maximizing the attraction of oppositely charged ions. (C) Signup and view all the answers

How does the size of a cation compare to its parent atom?

The cation is always smaller than its parent atom. (C) Signup and view all the answers

Compared to its parent atom, what is the typical size of an anion?

The anion is typically larger due to the addition of electrons. (C) Signup and view all the answers

If element X is in group 2, what charge is it most likely to form?

2+ (C) Signup and view all the answers

Which of the following ionic species has the smallest radius?

O$^{2+}$ (B) Signup and view all the answers

What is the most important requirement for the formation of a stable compound, according to Lewis structures?

Atoms achieving noble gas electron configurations (A) Signup and view all the answers

In a Lewis structure, what distinguishes bonding pairs from unshared pairs of electrons?

Bonding pairs are shared between two atoms, while unshared pairs are not. (C) Signup and view all the answers

When constructing Lewis structures, what is the first step after summing the valence electrons of all atoms in the molecule?

Using one pair of electrons to form a bond between each pair of bound atoms (C) Signup and view all the answers

For which element does the 'duet rule' apply when drawing Lewis Structures?

Hydrogen (B) Signup and view all the answers

What is the total number of valence electrons that should be accounted for when drawing the Lewis structure for carbon dioxide ($CO_2$)?

16 (A) Signup and view all the answers

After drawing single bonds between the central atom and surrounding atoms in a Lewis structure, how should the remaining valence electrons typically be arranged?

Arrange them to satisfy the octet rule for each second-row element and the duet rule for hydrogen. (B) Signup and view all the answers

Which of the following statements is correct regarding lone pairs in Lewis Structures?

Lone pairs are not shared and not involved in bonding. (C) Signup and view all the answers

What is the primary principle behind the VSEPR model in predicting molecular structure?

Minimizing the repulsion between electron pairs. (D) Signup and view all the answers

If a molecule has a central atom surrounded by four electron pairs, what is the arrangement that minimizes repulsion according to the VSEPR model?

Tetrahedral (B) Signup and view all the answers

Which of the following statements accurately describes a step in predicting molecular structure using the VSEPR model?

Draw the Lewis structure for the molecule to visualize electron pairs. (D) Signup and view all the answers

A molecule has three electron pairs around a central atom. According to the VSEPR model, what is the arrangement of these pairs to minimize repulsion?

Trigonal planar at 120° (C) Signup and view all the answers

What is the bond angle in a molecule with a tetrahedral arrangement of electron pairs around the central atom?

109.5° (C) Signup and view all the answers

How does the presence of lone pairs on the central atom affect the name of the molecular structure, compared to the arrangement of electron pairs?

If lone pairs are present, the molecular structure name will be different from the electron pair arrangement name. (A) Signup and view all the answers

A molecule has a central atom with two bonding pairs and two lone pairs. What is the arrangement of electron pairs and the molecular structure, respectively?

Tetrahedral, Bent (D) Signup and view all the answers

A molecule is found to have a linear arrangement of atoms. According to VSEPR theory, which of the following best describes the electron pair arrangement around the central atom?

Could be linear, trigonal planar, or tetrahedral depending on lone pairs (D) Signup and view all the answers

What is the primary purpose of arranging the remaining electrons around atoms in a Lewis structure?

To satisfy the octet rule for each second-row element and the duet rule for hydrogen. (A) Signup and view all the answers

Under what condition does a molecule exhibit resonance?

When more than one valid Lewis structure can be drawn for the molecule. (C) Signup and view all the answers

Which of the following best describes resonance structures?

Lewis structures that depict the different possible arrangements of electrons in a molecule. (B) Signup and view all the answers

Which of the following elements is most likely to form compounds with fewer than eight electrons around it?

Boron (B) Signup and view all the answers

Which of the following molecules is most likely to violate the octet rule?

NO (C) Signup and view all the answers

Considering their Lewis structures, which of the following molecules would you expect to exhibit resonance?

CO2 (C) Signup and view all the answers

What aspect of a molecule does its 'molecular structure' primarily describe?

The three-dimensional arrangement of atoms within the molecule. (C) Signup and view all the answers

How does understanding molecular structure contribute to predicting a molecule's properties?

It helps determine the bond angles and overall shape, affecting polarity and reactivity. (C) Signup and view all the answers

Electronegativity

The relative ability of an atom in a molecule to attract shared electrons to itself.

Electronegativity Trend

Electronegativity increases across a period (left to right) and decreases down a group (top to bottom).

Highest and Lowest Electronegativity

Fluorine (F) has the highest electronegativity (4.0), while Cesium (Cs) and Francium (Fr) have the lowest (0.7).