Draw Lewis structures for the following compounds, and predict which member of each pair will fo

step 1 All right, hi, everyone. Today we're going to be looking at a number of compounds, comparing two

Draw Lewis structures for the following compounds, and...

Key Concepts

Hydrogen Bonding

Hydrogen bonding is a type of intermolecular force that occurs when a hydrogen atom covalently bonded to a highly electronegative atom (typically nitrogen, oxygen, or fluorine) interacts with a lone pair of electrons on another electronegative atom. This interaction leads to unique properties like higher boiling points and enhanced solubility in polar solvents.

Lewis Structures

Lewis structures are visual representations of molecules that show how atoms are connected by bonds and where lone pairs of electrons are located. They are crucial for predicting molecular geometry, reactivity, and understanding the distribution of electrons that affects intermolecular forces such as hydrogen bonding.

Electronegativity

Electronegativity is a measure of an atom's tendency to attract electrons in a chemical bond. Differences in electronegativity between bonded atoms create polar bonds, which are essential for forming dipole-dipole interactions and hydrogen bonds when hydrogen is attached to atoms like nitrogen or oxygen.

Molecular Polarity

Molecular polarity results from the combination of individual bond polarities and the overall geometry of a molecule. A molecule that is asymmetrical with polar bonds will have a net dipole moment, enhancing its ability to engage in intermolecular interactions like hydrogen bonding.

Transcript

00:01 All right, hi, everyone.

00:02 Today we're going to be looking at a number of compounds, comparing two of them to each other and determining which of the two has the ability to create hydrogen bonds.

00:12 And to do that, we're going to use lewis dot structure to show how electrons are shared between the atoms in those compounds.

00:21 So the two we're going to start with today are ammonia, which is nh3, and arsenic trihydride, which is asha3.

00:32 Yes, h3.

00:33 Sorry, guys.

00:36 So before i start anything with lewis.

00:37 Dot structures, i like to take a look at how many valence electrons i know each of my atoms is going to need.

00:43 So we'll start with nitrogen.

00:46 Based on where nitrogen is located on the periodic table, we know that it is going to require three additional electrons to complete its outermost shell.

00:59 So nitrogen has five valence electrons in its outermost shell.

01:05 Hydrogen, hydrogen and helium, their first shell is actually going to hold only two electrons.

01:14 And hydrogen is our first element, and so it has one valence electron, and it's going to require one additional electron in order to complete its outermost shell.

01:25 And then arsenic is actually found in the exact same column as nitrogen, which means it's going to have the same number of valence electrons.

01:32 So arsenic will also have five valence electrons, meaning that it will require three additional electrons to complete its outermost shell.

01:45 So looking at this, it will appear that these elements are going to look very similar.

01:51 And it's true that each is only going to require three hydrogens in order to complete its outermost shell.

01:56 But then we'll talk a little bit more to figure out which of these two will actually form hydrogen bonds and explain why that's different.

02:02 So when we look at nitrogen, we know we have our two electrons here that are paired up together, and then nitrogen is going to share its electrons with hydrogen in three locations and create a loosed dot structure that looks something like this.

02:18 And again, arsenic is going to look very similar.

02:21 So arsenic here with its pair of electrons at top, sharing one electron between itself and hydrogen.

02:32 So that both of these have completed outermost shell.

02:38 Now, when nitrogen and arsenic are sharing electrons with the hydrogen atoms, the strength with which those atoms are going to be pulling the electrons towards their nucleus is going to differ depending on its location within the periodic table.

02:57 It's kind of the easiest way to figure that out.

02:59 So nitrogen is actually at the top of the column in the periodic table that it shares with arsenic.

03:05 And that means that nitrogen is going to pull those electrons a little more strongly towards its nucleus than arsenic is going to.

03:15 Remember, as we go down the periodic table, we're adding more and more layers of electrons to the shells of our atom.

03:23 And so arsenic has kind of like a buffer between its negatively charged electron cloud space and its nucleus.

03:30 Nitrogens isn't as big.

03:32 And so nitrogen's positive charge is a little stronger pulling those electrons towards it.

03:39 And so the electrons from hydrogen are going to be slightly pulled in just a little bit towards the nitrogen nucleus, more so than they're going to be for arsenic.

03:51 And so because of that, well, i can't draw today.

03:56 Our hydrogen atoms are going to end up with just a slightly positive charge because this.

04:04 They're losing their electron just a little bit more than the nitrogen is sharing.

04:11 And so nitrogen side is going to have a negative, a slightly negative charge...

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