Give the Lewis structure, molecular structure, and...

Key Concepts

Lewis Structures

Lewis structures are diagrams that show the arrangement of electrons in a molecule. They illustrate the bonding between atoms as well as lone pairs of electrons that may be present, helping to determine the molecule's stability and formal charge distribution.

Molecular Geometry

Molecular geometry refers to the three?dimensional arrangement of atoms in a molecule. It is explained by VSEPR theory, which predicts shapes based on the repulsions between electron pairs (bonding and nonbonding) around a central atom, thereby influencing properties like bond angles and molecular polarity.

Hybridization

Hybridization is the concept of mixing atomic orbitals to form new, equivalent hybrid orbitals that can form bonds with proper orientation and energy compatibility. This model aids in explaining the observed molecular geometries and bond angles as it reflects the underlying electron orbital structure.

Oxidizing Agents

An oxidizing agent is a substance that gains electrons in chemical reactions, thereby oxidizing another substance. The strength of an oxidizing agent is influenced by factors such as the electronegativity of the atoms involved and the molecule’s ability to stabilize additional negative charge, which in turn affects its reactivity in redox processes.

Transcript

00:03 So in this video, we're going to talk about questions that's the 8 from chapter 20, which says, give the lewish structure, molecular structure, and hybridization of the oxygen atom for of2.

00:12 Would you expect of2 to be a strong oxidizing agent like o2f2, discussed in exercise 67? so it's worth talking about what we did in exercise 67.

00:21 So exercise 67 asked us to give the lewish structure bond angles and hybridization of oxygen in o2f2.

00:27 Then we're told that o2f2 is a vigorous oxidizing and fluorinating agent, and we're asked if oxidation states or formal charges are better for accounting for that high reactivity of o2f2.

00:39 So what we're going to do is go over what oxidation states and formal charges are.

00:43 Then we'll draw the lewish structure for o2f2, assign oxidation states in formal charges, decide which one of those is better for accounting for the high reactivity of o2f2.

00:56 And then we'll use that when we're analyzing the lewis structure for o2.

01:01 So what's formal charge? formal charge is the charge on an atom, assuming that the electrons in a bond are shared evenly between the two bonded atoms.

01:11 So the formal charge is equal to the number of valence electrons minus the number of lone pair electrons on the atom, minus half of the number of bonded electrons.

01:21 Then we have the oxidation state, where different from where our electrons are shared evenly in formal charge, in our oxidation state, we are assuming that the more electronegative atom will take all of the electrons in the bond.

01:35 So then the oxidation state for the more electronegative atom is equal to the number of valence electrons minus the number of lone pair electrons minus the number of lone pair electrons.

01:52 So the difference between formal charge and oxidation state is that in formal charge, we assume electrons are shared evenly, in a bond, but in oxidation state, we assume that the more electronegative atom is going to take all of the electrons in a bond.

02:08 So, o2f2.

02:10 We know that oxygen has six valence electrons and fluorine has seven valence electrons.

02:14 That gives us 12 plus 14.

02:16 We have 26 electrons overall.

02:19 So let's go ahead and start drawing our lewish structure.

02:22 So we know that our fluorine likes to make just one single bond.

02:27 So we'll single bond it to our two oxygens.

02:30 And then we'll go ahead and fill in the octet on our foreign atoms.

02:37 That gives us eight electrons left over so we can put two long pairs on each oxygen.

02:45 And that's it.

02:46 That's all 26 electrons.

02:48 So now above each atom, i'm going to write the formal charge and below each atom i'm going to write the oxidation state.

02:56 And then we'll compare what those say about the reactivity and whether or not that matches up with the reality that o2f2 is a very strong oxidizing agent.

03:04 So the formal charge on fluorine.

03:06 So we have seven valence electrons minus six lone pair electrons minus half of the electrons in our bonds, so minus one.

03:15 So seven minus six minus one gives us a formal charge of zero.

03:19 And it's the same story for our other fluorine atom on the other side of the molecule.

03:23 Both have a formal charge of zero.

03:25 Now for our oxygen atom, we have six valence electrons minus four lone pair electrons minus half of the four electrons that are and the bonded electrons.

03:37 So 6 minus 4 minus 2 gives this a formal charge of 0.

03:43 And it's the same story for the other oxygen atom.

03:45 So the formal charges on this are all zero, which would indicate that this is not a very reactive molecule.

03:51 It doesn't indicate that strong oxidizing property that we know 0 -2f2 has.

03:57 But let's see what our oxidation states say about this.

04:01 So which ones are more electrical? negative atoms.

04:05 So in our oxygen fluorine bonds, the fluorine is more electronegative than the oxygen.

04:10 So it'll take all of our, it'll take all of the electrons when we're, when we're talking about bonds between fluorine and oxygen...

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