Question

activity a:
simple molecules
get the gizmo ready:

• check that the free build mode is selected.
• if necessary, double - click on the trash can icon to

clear the simulation area.

introduction: not every group of bonded atoms is a molecule. in a molecule, the chemical
bonds connecting atoms are covalent bonds. in a covalent bond, bonded atoms share pairs of
electrons. (in an ionic bond, electrons are transferred from one atom to another.)

question: what is the structure and chemical formula of simple molecules?

1. explore: on your own, experiment by dragging different atoms into the simulation screen

and bond them together. when you have completed a molecule, try typing its formula into
the \type formula\ box. see if you can figure out how to write formulas for simple molecules.

when you enter the correct formula for a
molecule you built, it appears in the
completed molecules area. which
molecules have you completed so far?

1. list: drag each element into the area. how many bonds can each element form?

carbon: _ nitrogen: _ chlorine: _ sulfur: _ hydrogen: _ oxygen: _

which element forms the greatest number of bonds? ______________

1. create: clear the simulation area, then drag two oxygen atoms into the area.

a. create a bond between the two oxygen atoms. how many bonds does each atom
have remaining? _______

b. click on the bond. what happens? __________________________________________

this is a double covalent bond. in this bond, two pairs of electrons are shared.

c. enter the formula o₂ into the box, then view the 3d molecule. notice the subscript
\2\ follows the element it describes, in this case oxygen.

1. create: clear the screen, then drag out two nitrogen atoms. bond them together to form a

complete n₂ molecule. what type of bond do you think you formed? ____________________

enter the formula into the area, then view the 3d nitrogen gas molecule. nitrogen molecules
contain triple bonds, so they share three pairs of electrons.

(activity a continued on next page)

Explanation:

• Carbon: Has 4 valence electrons, so it can form 4 bonds.
• Nitrogen: Has 5 valence electrons, needs 3 more to complete octet, so forms 3 bonds.
• Chlorine: Has 7 valence electrons, needs 1 more, so forms 1 bond.
• Sulfur: Similar to oxygen (group 16), has 6 valence electrons, needs 2 more, can form 2 bonds (but can also have expanded octet in some compounds, but in simple covalent bonding context here, 2).
• Hydrogen: Has 1 valence electron, needs 1 more, forms 1 bond.
• Oxygen: Has 6 valence electrons, needs 2 more, forms 2 bonds.
• Greatest number of bonds: Carbon (4).
• 3A: Each oxygen atom had 2 bonding sites (valence electrons needing to be shared). After forming a double bond (2 bonds between the two O atoms), each has \(2 - 2=0\) bonds remaining.
• 3B: Clicking on the bond (in the simulation context) likely changes the bond type (e.g., from single to double as described).
• 4: Nitrogen has 5 valence electrons. To complete the octet (for each N atom in \(N_2\)), they share 3 pairs of electrons, so it's a triple covalent bond.

Answer:

1. (Depends on user's simulation, no specific answer can be given from the text, user - dependent)
2. Carbon: 4; Nitrogen: 3; Chlorine: 1; Sulfur: 2; Hydrogen: 1; Oxygen: 2; Greatest number of bonds: Carbon
3. A. 0; B. (In simulation context, likely changes bond to double as per description); C. (No calculation, just formula entry as per instruction)
4. Triple covalent bond