Question 1

An expanded octet may occur:

Accepted Answer

A)  in the 1st and 2nd period only
B)  in families IA,IIA,and IIIA only
C)  anywhere except period 1 and 2
D)  in all families except IA
E)  in the 3rd and 4th period only

Question 2

Compound EX4 reacts with Y2 giving two products: EX3Y and XY.Calculate the E-X bond enthalpy if the reaction liberates 243.6 kJ/mol and other bond enthalpies are: Y-Y 109 kJ/mol,X-Y 123.1 kJ/mol and E-Y 290 kJ/mol.

Accepted Answer

A)  60.5 kJ/mol
B)  547.7 kJ/mol
C)  20.6 kJ/mol
D)  234.7 kJ/mol
E)  176.9 kJ/mol

Question 3

What is the molecular shape of BrF5?

Accepted Answer

A)  linear
B)  square pyramidal
C)  square planar
D)  octahedral
E)  trigonal bipyramidal

Question 4

Write a Lewis structure for sodium iodide.

Accepted Answer

A)   
B)   
C)   
D)   Na-I
E)

Question 5

How many lone pairs of electrons are on the As atom in AsCl3?

Accepted Answer

A)  0
B)  1
C)  2
D)  3

Question 6

The core electrons are called valence electrons.

Accepted Answer

A) True 
 B)False

Question 7

Write a Lewis structure for calcium hydride.

Accepted Answer

A)   
B)   
C)   
D)   H-Ca-H
E)   Ca-H

Question 8

Which of the following exhibits ionic bonding?

Accepted Answer

A)  C2H6 
B)  Na2S
C)  H2CO
D)  SiCl4 
E)  SF4

Question 9

Valence electrons are:

Accepted Answer

A)  all electrons of the last noble gas configuration
B)  electrons in filled orbits
C)  electrons in the shell of the highest principal quantum number
D)  unpaired electrons
E)  paired electrons

Question 10

After drawing the Lewis dot structure for BeCl2,determine the number of single bond(s) ,double bond(s) ,and lone pair(s) on the central atom.

Accepted Answer

A)  single bond(s) = 2,double bond(s) = 0,lone pair(s) = 0
B)  single bond(s) = 2,double bond(s) = 0,lone pair(s) = 2
C)  single bond(s) = 2,double bond(s) = 0,lone pair(s) = 1
D)  single bond(s) = 0,double bond(s) = 2,lone pair(s) = 0
E)  single bond(s) = 1,double bond(s) = 1,lone pair(s) = 0

Question 11

Given the bond enthalpies H-O (464) ,Cl-Cl (243) ,Cl-O (205) ,and H-Cl (431) in kJ/mol,compute ΔH° in kJ/mol for: 
H2O(g) + Cl2(g) → HOCl(g) + HCl(g) .

Accepted Answer

A)  -393 kJ/mol
B)  -1100 kJ/mol
C)  +71 kJ/mol
D)  +393 kJ/mol
E)  +1100 kJ/mol

Question 12

After drawing the Lewis dot structure for IF7,determine the number of single bond(s) ,double bond(s) ,and lone pair(s) on the central atom.

Accepted Answer

A)  single bond(s) = 3,double bond(s) = 2,lone pair(s) = 1
B)  single bond(s) = 7,double bond(s) = 0,lone pair(s) = 1
C)  single bond(s) = 7,double bond(s) = 0,lone pair(s) = 0
D)  single bond(s) = 1,double bond(s) = 0,lone pair(s) = 0
E)  single bond(s) = 4,double bond(s) = 0,lone pair(s) = 0

Question 13

What is the correct molecular geometry for the carbon atom in urea (NH2) 2CO?

Accepted Answer

A)  Tetrahedral
B)  T-Shaped
C)  Trigonal planar
D)  Trigonal pyramidal
E)  Trigonal bipyramidal

Question 14

Given the bond enthalpies I-Cl (209) ,H-H (435) ,H-I (297) ,and H-Cl (431) in kJ/mol,compute ΔH° in kJ/mol for: ICl3(g) + 2 H2(g) → HI(g) + 3 HCl(g) .

Accepted Answer

A)  +264 kJ/mol
B)  -84 kJ/mol
C)  -93 kJ/mol
D)  -523 kJ/mol
E)  +84 kJ/mol

Question 15

Choose the INCORRECT statement.

Accepted Answer

A)  A Lewis symbol consists of a chemical symbol and the outer shell electrons.
B)  In a Lewis symbol,the chemical symbol represents the nucleus of the atom.
C)  A Lewis structure is a combination of Lewis symbols that represent the transfer or sharing of electrons in a chemical bond.
D)  An ion written as a Lewis symbol has brackets outside the electrons.
E)  An ion written as a Lewis symbol has the charge written as a superscript outside the closing bracket.

Question 16

The compound ClF  contains:

Accepted Answer

A)  ionic bonds
B)  nonpolar covalent bonds
C)  polar covalent bonds with partial negative charges on the F atoms
D)  polar covalent bonds with partial negative charges on the Cl atoms

Question 17

After drawing the Lewis dot structure of HCN,pick the INCORRECT statement from the following.

Accepted Answer

A)  The C-N bond is a double bond.
B)  There are no lone pairs on C.
C)  The C-H bond is a single bond.
D)  There is a lone pair of electrons on N.
E)  There are no lone pairs on H.

Question 18

How many "dots" should be shown for the oxygen symbol in lithium oxide?

Accepted Answer

A)  2
B)  4
C)  6
D)  8
E)  10

Question 19

What is the formal charge on N in NO3-?

Accepted Answer

A)  +2
B)  -2
C)  +1
D)  -1
E)  0

Question 20

How many bond pairs ("bp") and how many lone pairs ("lp") should be shown in the Lewis structure for carbon monoxide?

Accepted Answer

A)  1 bp/4 lp
B)  2 bp/3 lp
C)  3 bp/2 lp
D)  4 bp/1 lp
E)  5 bp/0 lp

Exam 10: Chemical Bonding I: Basic Concepts

After drawing the Lewis dot structure for BeCl2,determine the number of single bond(s) ,double bond(s) ,and lone pair(s) on the central atom.

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The compound ClF contains:

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Write a Lewis structure for sodium iodide.

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Given the bond enthalpies I-Cl (209) ,H-H (435) ,H-I (297) ,and H-Cl (431) in kJ/mol,compute ΔH° in kJ/mol for: ICl3(g) + 2 H2(g) → HI(g) + 3 HCl(g) .

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What is the formal charge on N in NO3-?

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Compound EX4 reacts with Y2 giving two products: EX3Y and XY.Calculate the E-X bond enthalpy if the reaction liberates 243.6 kJ/mol and other bond enthalpies are: Y-Y 109 kJ/mol,X-Y 123.1 kJ/mol and E-Y 290 kJ/mol.

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The core electrons are called valence electrons.

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What is the correct molecular geometry for the carbon atom in urea (NH2) 2CO?

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Write a Lewis structure for calcium hydride.

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An expanded octet may occur:

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After drawing the Lewis dot structure of HCN,pick the INCORRECT statement from the following.

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How many lone pairs of electrons are on the As atom in AsCl3?

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After drawing the Lewis dot structure for IF7,determine the number of single bond(s) ,double bond(s) ,and lone pair(s) on the central atom.

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Given the bond enthalpies H-O (464) ,Cl-Cl (243) ,Cl-O (205) ,and H-Cl (431) in kJ/mol,compute ΔH° in kJ/mol for: H2O(g) + Cl2(g) → HOCl(g) + HCl(g) .

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Valence electrons are:

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Choose the INCORRECT statement.

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How many bond pairs ("bp") and how many lone pairs ("lp") should be shown in the Lewis structure for carbon monoxide?

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What is the molecular shape of BrF5?

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Which of the following exhibits ionic bonding?

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How many "dots" should be shown for the oxygen symbol in lithium oxide?

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After drawing the Lewis dot structure for BeCl_2,determine the number of single bond(s) ,double bond(s) ,and lone pair(s) on the central atom.

Correct Answer
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Given the bond enthalpies I-Cl (209) ,H-H (435) ,H-I (297) ,and H-Cl (431) in kJ/mol,compute ΔH° in kJ/mol for: ICl₃(g) + 2 H₂(g) → HI(g) + 3 HCl(g) .

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What is the formal charge on N in NO₃^-?

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Compound EX₄ reacts with Y₂ giving two products: EX₃Y and XY.Calculate the E-X bond enthalpy if the reaction liberates 243.6 kJ/mol and other bond enthalpies are: Y-Y 109 kJ/mol,X-Y 123.1 kJ/mol and E-Y 290 kJ/mol.

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What is the correct molecular geometry for the carbon atom in urea (NH₂) ₂CO?

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How many lone pairs of electrons are on the As atom in AsCl₃?

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After drawing the Lewis dot structure for IF_7,determine the number of single bond(s) ,double bond(s) ,and lone pair(s) on the central atom.

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Given the bond enthalpies H-O (464) ,Cl-Cl (243) ,Cl-O (205) ,and H-Cl (431) in kJ/mol,compute ΔH° in kJ/mol for: H₂O(g) + Cl₂(g) → HOCl(g) + HCl(g) .

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What is the molecular shape of BrF₅?

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