Skip to content

HW: What makes some bonds stronger and other bonds weaker?

Electron Shells, Bond Length and Bond Energies:  Use the Supplement: Electron Shells and Bond Length/Energy Chart and answer the following questions.

  1. For each period on the periodic table, count and record the number of energy levels or shells around the nucleus.
Period Number of Shells
1 1
2 2
3 3
4 4
5 5
6 6
7 7
  1. Fuel reactions use the same elements of life that we studied in Unit 1:  H, C, and O. Complete the table by determining the atomic number, number of protons, number of electrons in each energy level, and number of valence electrons. Create an atomic model for each of these elements by placing the correct number of electrons in the correct electron shell. Only include the electrons in your model; not the protons and the neutrons in the nucleus.
Hydrogen Carbon Oxygen
Atomic Number: 1
In the nucleus:
No. of Protons: 0
No. of Neutrons: 1
in the energy shells:
No. electrons in 1st shell: 1
No. electrons in 2nd shell: 0
No. valence electrons: 1		 Atomic Number: 6
In the nucleus:
No. of Protons: 6
No. of Neutrons: 6
in the energy shells:
No. electrons in 1st shell: 2
No. electrons in 2nd shell: 4
No. valence electrons: 4		 Atomic Number: 8
In the nucleus:
No. of Protons: 8
No. of Neutrons: 8
in the energy shells:
No. electrons in 1st shell: 2
No. electrons in 2nd shell: 6
No. valence electrons: 6

  1. The radius of an atom is the distance from the nucleus to the outermost electron. Based on your shell models, which element has the smallest atomic radius-H, C or O? Write a statement that connects the number of shells to the atomic radius.

    Hydrogen would have the smallest radius due to it having only one shell of electrons.

  2. Bond Length is the distance from the nucleus of one atom to the nucleus of the second atom in a bond.  

    1. Based on the atomic radius of H and C, which covalent bond do you predict will have the longest bond length, H-H or C-H? Explain your reasoning. The H-H bond would have a shorter length because the radius of the atom is smaller. So the C-H bond would be longer than H-H

  3. Bond Energy is the energy required to break a bond. Look at the chart of Bond Length and Bond Energy.  Find each bond type and complete the table by recording the bond length and bond energy.

Bond Type Bond Energy (kJ/mol) Bond Length (pm)
H - F 565 92
H - Cl 427 127
H - Br 363 141
H - I 295 161
<<<<<<< HEAD

1. For the halogens, which are the elements in Group 17 on the periodic table, what is the relationship between the energy of a bond and the length of the bond? Explain your reasoning.

1. For the halogens, which are the elements in Group 17 on the periodic table, what is the relationship between the energy of a bond and the length of the bond? Explain your reasoning.

origin/main The length of the bond is inversely proportional to enter energy in the bond. As the distance between the atoms gets larger,

  1. Find each bond type and complete the table by recording the bond length and bond energy.
Bond Type Bond Energy (kJ/mol) Bond Length (pm)
C = O 745 120
C - O 385 143
<<<<<<< HEAD
  1. What is the relationship between the energy of the bond and the number of bonds (single bond, double bond)? Explain your reasoning.

=======

1. What is the relationship between the energy of the bond and the number of bonds (single bond, double bond)? Explain your reasoning.

origin/main Double bonds have more energy because there are more electrons being shared between the atoms.

  1. Does your relationship hold true for carbon with multiple bonds (C-C, C=C, C≡C) and nitrogen with multiple bonds (N-N, N=N, N≡N)? State evidence to support your answer.

    yes, all ot the triple bonded atoms had the shortest distance and also the highest energy of any combination.

  2. Length measurements. (Google answers as needed.)

    1. What does a (pm) stand for in length measurements? 1 picometer
    2. How many meters are in 75 pm? Use scientific notation and show your work. \(\(7.5*10^{-11}\)\)

  3. Energy measurements. (Google answers as needed.)

    1. What unit does kilojoules (kJ) represent in energy? 1000 Joules
    2. What is the definition of a Joule (J)?  Power(Energy per unit time)
    3. What unit does mole (mol) represent? <<<<<<< HEAD
\[6.02214076*10^{23}\]
  1. What is the definition of a mole?

  2. ======= \(\(6.02214076*10^{23}\)\)

    1. What is the definition of a mole?

      origin/main The SI Unit of the amount of substance

  3. Watch the TedTalk on the Mole.  Write three things that you learned from the video.

    1. it was created by Avogadro
    2. you can use it to convert from AMU's to grams or ml
    3. it can also be worded as 602 sextillion

*Turn in this completed “L4.7 Pre-Lesson Worksheet” to the HW post on schoology before classes resume after break

REVIEW & REINFORCE:

Use the following sections of the textbook to help you review materials that were covered in this lesson

Last update: June 5, 2023
Created: June 5, 2023