Write Lewis structures that obey the octet rule (duet rule for H ) for each of the following mol

Write Lewis structures that obey the octet rule (duet rule...

Write Lewis structures that obey the octet rule (duet rule for $\mathrm{H}$ ) for each of the following molecules. Carbon is the central atom in $\mathrm{CH}_{4}$, nitrogen is the central atom in $\mathrm{NH}_{3}$, and oxygen is the central atom in $\mathrm{H}_{2} \mathrm{O}$. a. $\mathrm{F}_{2}$ e. $\mathrm{NH}_{3}$ b. $\mathrm{O}_{2}$ f. $\mathrm{H}_{2} \mathrm{O}$ c. $\mathrm{CO}$ g. HF d. $\mathrm{CH}_{4}$

Write Lewis structures that obey the octet rule (duet rule for $\mathrm{H}$ ) for each of the following molecules. Carbon is the central atom in $\mathrm{CH}_{4}$, nitrogen is the central atom in $\mathrm{NH}_{3}$, and oxygen is the central atom in $\mathrm{H}_{2} \mathrm{O}$.
a. $\mathrm{F}_{2}$
e. $\mathrm{NH}_{3}$
b. $\mathrm{O}_{2}$
f. $\mathrm{H}_{2} \mathrm{O}$
c. $\mathrm{CO}$
g. HF
d. $\mathrm{CH}_{4}$

Key Concepts

Lewis Structures

Lewis structures are diagrams that represent the bonding between atoms in a molecule and the lone pairs of electrons that may exist. These structures use dots to represent electrons and lines to represent bonds, providing a simple method to visualize the arrangement of valence electrons in molecules.

Octet Rule

The octet rule states that atoms tend to form bonds in such a way that each atom (except hydrogen) is surrounded by eight electrons in its valence shell, mimicking the electron configuration of a noble gas. This rule guides the formation of stable molecules and helps predict molecular structures.

Duet Rule for Hydrogen

The duet rule for hydrogen is a specific rule stating that hydrogen atoms are stable with only two electrons in their valence shell, because hydrogen has only one orbital that can be occupied. This rule is an exception to the octet rule and is crucial when drawing Lewis structures involving hydrogen.

Transcript

00:01 Problem 85 says to write a lewis structure for each molecule that obeys the octet rule or the duet rule for hydrogen.

00:11 So the first part here, part a, is fluorine gas.

00:19 So one of the main things to keep in mind when drawing allue as structure is keep in mind how many electrons the whole molecule should have.

00:31 And two, make sure that each atom in the molecule has the correct number of valence electrons, which you can find by looking at the periodic table, and make sure that its electron, basically its electron shell is filled, so you want eight around each atom in general.

00:55 So for fluorine gas, we have a single bond between the fluorine atoms, and then keep in mind that each fluorine has seven valence electrons.

01:05 So this bond between them counts for one each, and then we have two, three, four, five, six, seven.

01:14 Two, three, four, five, six, seven.

01:18 So because each bond is two electrons, that means each of these fluorines now has eight electrons, which obeys the octet rule.

01:27 Each has seven valence electrons, and because we're looking for two times seven valence electrons, we should have 14 electrons total.

01:38 That's 2, 4, 6, 8, 10, 12, 14.

01:42 This obeys the parameters set out by the problem.

01:47 So you can do the same thing for each of these molecules here.

01:55 Oxygen has six valence electrons.

01:58 So we're looking for 12 electrons total.

02:00 Filling out the octet roll for each of these oxygens.

02:05 So in general, like i said, oxygen has six valence electrons, and we want there to be 12 electrons total.

02:25 So right now we have two, four, six, eight, ten, twelve.

02:32 But these guys aren't found yet.

02:34 So the best way to satisfy the number of electrons total in this molecule as well as the number of valence per oxygen and making sure that each oxygen has a total of eight electrons surrounding it is to give these two oxygens a double bond.

02:56 Oops.

03:01 That way we can maintain the six electron rule per oxygen, but still make sure that we have a total of 12 electrons.

03:13 For carbon monoxide, carbon has four valence, oxygen has six, like we saw on the previous, so we're looking for 10 electrons total.

03:25 So i won't belabor this too much, but the best way for for carbon and oxygen to both have the appropriate, or close to the appropriate number of valence electrons.

03:38 Sometimes it doesn't work out...

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