Question 1

Consider a molecule with the following connections: 
When a valid electron dot structure is written,how many double bonds will the molecule contain?
A)0
B)1
C)2
D)4

Accepted Answer

Based on the given connections, the molecule contains 11 atoms - hence, it is too complex to draw the electron dot structure without additional information. However, we can make a general assumption that the molecule would contain various types of bonds, including single and double bonds. Double bonds occur when two atoms share two pairs of electrons, which is very common in organic molecules. Therefore, it is reasonable to assume that the electron dot structure of the given molecule would have at least one double bond. Looking at the answer choices, the only option with at least one double bond is C. Therefore, the best choice is C.

Question 2

Which molecule contains a triple bond? A)F₂ B)O₃ C)HCN D)H₂CO

Accepted Answer

HCN (hydrogen cyanide) contains a triple bond between the carbon and nitrogen atoms.

Question 3

How many electrons are in the valence shell of I in IF₄^-? A)8 B)10 C)12 D)14

Accepted Answer

The answer of How many electrons are in the valence...

Question 4

Which is the most acceptable electron dot structure for N₂H₂? A) B) C) H - N =N - H D)

Accepted Answer

The answer of Which is the most acceptable electron dot...

Question 5

Identify the fourth-row element X that forms the ion. 
A)Ge
B)As
C)Se
D)Kr

Accepted Answer

The answer of Identify the fourth-row element X that forms...

Question 6

How many lone pairs of electrons are on the P atom in PF₃? A)0 B)1 C)2 D)3

Accepted Answer

PF5 molecule has 5 bonding pairs and no lone pairs of electrons on the P atom. However, when one F atom is replaced by a more electronegative O atom in PF4F, a lone pair of electrons is introduced on the P atom due to the higher electron density around the O atom. In PF₃, there is only one F atom replaced by a compound or a radical, which does not introduce any lone pairs. Hence, there is only one lone pair of electrons on the P atom in PF₃. Therefore, the correct choice is B.

Question 7

The phosphorus atom in PCl₃ would be expected to have a A)partial positive (δ+)charge. B)partial negative (δ-)charge. C)3+ charge. D)3- charge.

Accepted Answer

The electronegativity of chlorine (3.16) is higher compared to that of phosphorus (2.19). That means the chlorine atoms will pull electrons towards themselves, making the P atom partially positive (δ+).

Question 8

A::A represents
A)a double bond.
B)a quadruple bond.
C)one lone pair of electrons.
D)two lone pairs of electrons.

Accepted Answer

A:A represents a double bond between two atoms.

Question 9

Arrange the following in order of increasing ionic character: Al₂S₃,MgS,Na₂S,P₄S₃,S₈. A)MgS,Na₂S,Al₂S₃,P₄S₃,S₈ B)Na₂S,MgS,Al₂S₃,P₄S₃,S₈ C)S₈,P₄S₃,Al₂S₃,MgS,Na₂S D)S₈,P₄S₃,Al₂S₃,Na₂S,MgS

Accepted Answer

The answer of Arrange the following in order of increasing...

Question 10

Elements that can accommodate more than eight electrons in their valence shell occur only in periodic table period
A)2 or lower.
B)3 or lower.
C)4 or lower.
D)5 or lower.

Accepted Answer

The answer of Elements that can accommodate more than eight...

Question 11

How many of the σ bonds in H₂SO₄ are coordinate covalent bonds? A)0 B)2 C)4 D)6

Accepted Answer

In the given compound, sulfur atoms are capable of forming coordinate covalent bonds as they can donate a lone pair of electrons to the central atom. The two sulfur atoms attached to the central Os (osmium) atom are forming coordinate covalent bonds. Therefore, the answer is 2 (choice B).

Question 12

Which of the following contains an atom that does not obey the octet rule? A)KBr B)CO₂ C)ClF₃ D)ICl

Accepted Answer

ClF₃ contains chlorine, which can have more than 8 electrons in its valence shell due to the presence of d-orbitals, thus not obeying the octet rule.

Question 13

The nitrogen-nitrogen bond in :N=N: has a bond order of
A)3
B)1
C)2
D)6

Accepted Answer

The answer of The nitrogen-nitrogen bond in :N=N: has a...

Question 14

The electronegativities for the elements vary from 0.7 for cesium to 4.0 for fluorine.The electronegativity for iodine is 2.5.Based entirely on the general guidelines for electronegativities and bond character,
A)binary compounds with iodine should all be polar covalent with a δ- on I.
B)binary compounds with iodine should all be polar covalent with a δ+ on I.
C)compounds with iodine may be ionic,polar covalent,or nonpolar covalent.
D)no binary compounds with iodine should be substantially ionic.

Accepted Answer

The answer of The electronegativities for the elements vary from...

Question 15

Element A has an electronegativity of 0.8 and element B has an electronegativity of 3.0.Which statement best describes the bonding in A₃B? A)The AB bond is largely covalent with a δ- on A. B)The AB bond is largely covalent with a δ+ on A. C)The compound is largely ionic with A as the cation. D)The compound is largely ionic with A as the anion.

Accepted Answer

With a large difference in electronegativity between the elements, it is likely that the bonding will be largely ionic. In this case, element B is much more electronegative than A, suggesting that A will most likely give up its electrons to form cations, while B will accept those electrons to form anions. Therefore, the compound is largely ionic with A as the cation.

Question 16

A chlorine atom in Cl₂ should have a A)charge of 1-. B)partial charge δ-. C)partial charge δ+. D)charge of 0.

Accepted Answer

In Cl2, two chlorine atoms share electrons equally in a covalent bond, resulting in no charge on each atom.

Question 17

Which element can accommodate more than eight electrons in its valence shell?
A)C
B)O
C)P
D)He

Accepted Answer

Phosphorus (P) can expand its valence shell to accommodate more than eight electrons due to the availability of d-orbitals.

Question 18

How many lone pairs of electrons are on the Xe atom in XeF₆? A)0 B)1 C)2 D)3

Accepted Answer

XeF6 has a total of 8 valence electrons from Xe. After forming 6 bonds with F atoms, 2 electrons remain as one lone pair on Xe.

Question 19

Based on the indicated electronegativities,arrange the following in order of increasing ionic character: CsBr,LaBr₃,PBr₃,MgBr₂. A)CsBr,LaBr₃,MgBr₂,PBr₃ B)CsBr,MgBr₂,PBr₃,LaBr₃ C)PBr₃,LaBr₃,MgBr₂,CsBr D)PBr₃,MgBr₂,LaBr₃,CsBr

Accepted Answer

The increasing order of ionic character is based on the difference in electronegativity between the cation and anion. The larger the difference, the more ionic character the compound will have.

CsBr has the largest difference in electronegativity, followed by MgBr2, PBr3, and LaBr3. Therefore, CsBr has the most ionic character, while LaBr3 has the least.

The correct order of increasing ionic character is:

MgBr2 < PBr3 < LaBr3 < CsBr

Therefore, choice D is the best option, as it correctly arranges the compounds in this order.

Question 20

In the most acceptable electron-dot structure for carbonyl fluoride,COF₂ the central atom is A)C,which is singly-bonded to O. B)C,which is doubly-bonded to O. C)O,which is singly-bonded to C D)O,which is doubly-bonded to C.

Accepted Answer

In the electron-dot structure for carbonyl fluoride, the oxygen and fluorine atoms are each singly bonded to carbon, leaving two lone pairs of electrons on the oxygen. The carbon atom is then doubly bonded to the oxygen, making it the central atom. Therefore, option B is the correct choice.

Quiz 7: Covalent Bonds and Molecular Structure

Consider a molecule with the following connections: When a valid electron dot structure is written,how many double bonds will the molecule contain?

Which molecule contains a triple bond?

How many electrons are in the valence shell of I in IF4-?

Which is the most acceptable electron dot structure for N2H2?

Identify the fourth-row element X that forms the ion.

How many lone pairs of electrons are on the P atom in PF3?

The phosphorus atom in PCl3 would be expected to have a

A::A represents

Arrange the following in order of increasing ionic character: Al2S3,MgS,Na2S,P4S3,S8.

Elements that can accommodate more than eight electrons in their valence shell occur only in periodic table period

How many of the σ bonds in H2SO4 are coordinate covalent bonds?

Which of the following contains an atom that does not obey the octet rule?

The nitrogen-nitrogen bond in :N=N: has a bond order of

The electronegativities for the elements vary from 0.7 for cesium to 4.0 for fluorine.The electronegativity for iodine is 2.5.Based entirely on the general guidelines for electronegativities and bond character,

Element A has an electronegativity of 0.8 and element B has an electronegativity of 3.0.Which statement best describes the bonding in A3B?

A chlorine atom in Cl2 should have a

Which element can accommodate more than eight electrons in its valence shell?

How many lone pairs of electrons are on the Xe atom in XeF6?

Based on the indicated electronegativities,arrange the following in order of increasing ionic character: CsBr,LaBr3,PBr3,MgBr2.

In the most acceptable electron-dot structure for carbonyl fluoride,COF2 the central atom is

How many electrons are in the valence shell of I in IF₄^-?

Which is the most acceptable electron dot structure for N₂H₂?

How many lone pairs of electrons are on the P atom in PF₃?

The phosphorus atom in PCl₃ would be expected to have a

Arrange the following in order of increasing ionic character: Al₂S₃,MgS,Na₂S,P₄S₃,S₈.

How many of the σ bonds in H₂SO₄ are coordinate covalent bonds?

Element A has an electronegativity of 0.8 and element B has an electronegativity of 3.0.Which statement best describes the bonding in A₃B?

A chlorine atom in Cl₂ should have a

How many lone pairs of electrons are on the Xe atom in XeF₆?

Based on the indicated electronegativities,arrange the following in order of increasing ionic character: CsBr,LaBr₃,PBr₃,MgBr₂.

In the most acceptable electron-dot structure for carbonyl fluoride,COF₂ the central atom is