Search found 43 matches

by Samantha Lee 1A
Wed Nov 25, 2020 11:28 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation Number
Replies: 1
Views: 17

Oxidation Number

I am still a little confused on oxidation numbers. Please let me know if my thought process is right. You get the formal charge of the atoms and compare it to the overall charge. Whatever is the difference is the oxidation number. Is that right, and is that the only way to find oxidation number?
by Samantha Lee 1A
Tue Nov 24, 2020 11:35 am
Forum: Hybridization
Topic: Hybridization techniques
Replies: 4
Views: 37

Re: Hybridization techniques

I have been having the same problem. It is easier if you think of hybridization in steps. First is the promotion of electron(s). Look at how many bonds you have and how many unpaired electrons in for example, p orbitals. If you have three bonds and only two electrons in p orbitals, you need to promo...
by Samantha Lee 1A
Tue Nov 24, 2020 11:33 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR formula
Replies: 4
Views: 13

Re: VSEPR formula

E represents a lone pair; For example, SCl4 has one lone pair and 4 bonds. Its VESPR formula would be AX4E. I hope that makes sense.
by Samantha Lee 1A
Mon Nov 23, 2020 11:52 am
Forum: Hybridization
Topic: Basic Explanation of Hybridization
Replies: 3
Views: 21

Basic Explanation of Hybridization

I am still confused about how to determine hybridization for each compound. I get how to write an electron configuration but still don't understand how the hybridization orbitals are created and when how we know the difference between a lone pair and just bonds on a hybridization orbital. Could some...
by Samantha Lee 1A
Mon Nov 23, 2020 11:49 am
Forum: Sigma & Pi Bonds
Topic: Sigma Bonds and Bond Length
Replies: 6
Views: 20

Re: Sigma Bonds and Bond Length

The way I think about it is that a single bond is a sigma bond, a double bond is a sigma and a pi bond, and a triple bond is a sigma and two pi bonds. I think that the general trends for a single, double, and triple bond relating length and strength would apply to sigma and pi bonds that make up eac...
by Samantha Lee 1A
Fri Nov 20, 2020 11:00 am
Forum: Hybridization
Topic: Energy level of sp3
Replies: 2
Views: 23

Re: Energy level of sp3

From what I know and looked up, "What is Hybridization? Redistribution of the energy of orbitals of individual atoms to give orbitals of equivalent energy happens when two atomic orbitals combine to form hybrid orbital in a molecule. This process is called hybridization. The new orbitals thus f...
by Samantha Lee 1A
Thu Nov 19, 2020 8:52 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles (<109 or 104.5, etc)
Replies: 8
Views: 26

Bond Angles (<109 or 104.5, etc)

When we are listing the bond angles on an exam, it is okay to just say it is less than a certain angle or do we have to know the specific bond angle? For example, less than 109 degrees or 104.5 degrees.
by Samantha Lee 1A
Wed Nov 18, 2020 12:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Position of lone pairs
Replies: 3
Views: 21

Re: Position of lone pairs

Yes - lone pairs should be as far away from each other as possible. As Dr. Lavelle said "additional lone pairs force bonding e- closer together". This also means that the lone pairs will repel each other, forcing the lone pairs to be as far apart as possible.
by Samantha Lee 1A
Tue Nov 17, 2020 11:17 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape generalities
Replies: 4
Views: 20

Re: Molecular Shape generalities

Yes - the molecular shape are the same for similar structures as the examples. If you look up VESPR charts on google, you can find a nice chart that breaks down the molecular shapes (general shapes). It helped me visualize what we covered in class.
by Samantha Lee 1A
Mon Nov 16, 2020 10:29 am
Forum: Determining Molecular Shape (VSEPR)
Topic: bent v. angular
Replies: 27
Views: 475

Re: bent v. angular

Both mean the same thing. My old chemistry teacher preferred bent, but I think Dr. Lavelle will accept either. I would make sure that you know that they mean the same thing in case one versus the other is used on the exam. For example, if one question asks about bent, while another question asks abo...
by Samantha Lee 1A
Sun Nov 15, 2020 6:35 pm
Forum: Lewis Structures
Topic: 2C.5 part a radical question
Replies: 2
Views: 11

Re: 2C.5 part a radical question

Hello! This might be a silly question, but are you referring to the semicolon next to the Cl atom in the problem? That's the only place I can see anything that resembles a lone electron. Otherwise, I might be looking at the wrong problem. No, I am not referring to the semicolon. After you draw out ...
by Samantha Lee 1A
Sun Nov 15, 2020 5:53 pm
Forum: Lewis Structures
Topic: 2C.5 part a radical question
Replies: 2
Views: 11

2C.5 part a radical question

I was wondering why the unpaired electron was placed on chlorine and not oxygen. This makes the formal charge +1 for Cl and -1 for O. Why isn't the unpaired electron not on oxygen?
by Samantha Lee 1A
Fri Nov 13, 2020 10:58 am
Forum: Determining Molecular Shape (VSEPR)
Topic: The shape
Replies: 5
Views: 50

Re: The shape

I don't think that it matter which atom you put the wedge and receding wedge on as long as it makes sense that one is pointing towards you and the one is receding away. The molecule can be rotated so as long as it makes sense visually, I think it does not matter.
by Samantha Lee 1A
Thu Nov 12, 2020 9:31 am
Forum: Lewis Structures
Topic: Length of bonds
Replies: 6
Views: 48

Re: Length of bonds

As far as I know, there is no specific number that the bond lengths differ. It's just important to know that a single bond is longer than a double bond because a double bond has more electrons so the attractive force between the nucleus is stronger. Dr. Lavelle said he would give us the bond lengths...
by Samantha Lee 1A
Wed Nov 11, 2020 11:23 am
Forum: Dipole Moments
Topic: Ranking Strength of Interactions
Replies: 1
Views: 20

Ranking Strength of Interactions

Is it safe to assume that an increase in surface area results in stronger interactions? What happens if there is a variation in surface area (shape) and electrons? Which is weighted more in terms of ranking strength of interactions?
by Samantha Lee 1A
Tue Nov 10, 2020 9:49 am
Forum: Bond Lengths & Energies
Topic: Dissociation Energy
Replies: 4
Views: 26

Re: Dissociation Energy

Dissociation energies are provided for a problem. There is no way to calculate it without doing experiments. You should be able to see the trend on the periodic table though. It is important to be able to rank elements in terms of high or low dissociation energies.
by Samantha Lee 1A
Tue Nov 10, 2020 9:47 am
Forum: Ionic & Covalent Bonds
Topic: Size of Bonds
Replies: 28
Views: 92

Re: Size of Bonds

Double bonds are shorter than single bonds because they are stronger. They are able to pull in electrons from the other atom better, which shrinks the size of the bond that holds the two atoms together.
by Samantha Lee 1A
Mon Nov 09, 2020 9:02 am
Forum: Administrative Questions and Class Announcements
Topic: Discussion Week 6 [ENDORSED]
Replies: 10
Views: 199

Discussion Week 6 [ENDORSED]

In Dr. Lavelle's email, he said that their was no discussion. Just to clarify, that means that all discussions (even those not on Wednesday) are cancelled, correct?
by Samantha Lee 1A
Fri Nov 06, 2020 1:26 pm
Forum: Ionic & Covalent Bonds
Topic: More Covalent Character
Replies: 2
Views: 26

More Covalent Character

I am still a little confused on how to tell which atom has more covalent character when the anion and cation differ. Please help.
by Samantha Lee 1A
Thu Nov 05, 2020 10:41 am
Forum: Resonance Structures
Topic: Expanded Octet Examples
Replies: 5
Views: 48

Re: Expanded Octet Examples

Expanded octet examples occur when there is a d-orbital open to hold additional electrons. This is anything in the 3rd period where the first d-orbital occurs.
by Samantha Lee 1A
Wed Nov 04, 2020 11:03 am
Forum: Lewis Structures
Topic: How do we know when an element will have more than 8 electrons?
Replies: 6
Views: 25

Re: How do we know when an element will have more than 8 electrons?

Today's lecture discussed the exceptions to the octet rule in detail. An element can have more than the octet due to d-orbitals. He also discussed elements that can have less than the octet rule. Looking at the placement of elements in the periodic table is the best approach.
by Samantha Lee 1A
Mon Nov 02, 2020 11:29 am
Forum: Resonance Structures
Topic: Delocalization of electrons
Replies: 10
Views: 73

Re: Delocalization of electrons

Anirudh Mahadev 1B wrote:Do delocalized electrons contribute to conductivity?


Delocalized electrons are freely able to move around. If the delocalized electrons are in metals, then a "sea" of delocalized electrons can be could electrical conductors.
by Samantha Lee 1A
Fri Oct 30, 2020 12:01 pm
Forum: Lewis Structures
Topic: Line in place of paired dots
Replies: 8
Views: 42

Line in place of paired dots

Are we able to use a solid line to indicate 2 electrons (not the bond)? ie) Flourine having 3 lines and one dot.
by Samantha Lee 1A
Thu Oct 29, 2020 11:16 am
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 30
Views: 337

Re: Atomic Radius

Atomic radius is highest at the bottom left of the periodic table. As you go down a group, another shell is added for the electrons, which increases the radius. It decreases as you move to the right of a period because their is a higher charge between the added electron and the nucleus (positive cha...
by Samantha Lee 1A
Wed Oct 28, 2020 1:16 pm
Forum: Trends in The Periodic Table
Topic: Elements with a low ionization energy
Replies: 6
Views: 57

Re: Elements with a low ionization energy

Think of the word ionization as "ions". That helps associate ionization with becoming ions. If there is a low ionization energy, then the element can lose an electron very easily and become an ion (cation).
by Samantha Lee 1A
Mon Oct 26, 2020 1:26 pm
Forum: Administrative Questions and Class Announcements
Topic: Un-Randomize Sapling
Replies: 2
Views: 22

Un-Randomize Sapling

Help. I cannot figure out how to unrandomize the homework on Sapling. Please help. Thank you
by Samantha Lee 1A
Mon Oct 26, 2020 10:20 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: z electrons
Replies: 8
Views: 40

z electrons

I am still confused on what z electrons are? Can someone please clarify. Thank you
by Samantha Lee 1A
Fri Oct 23, 2020 12:34 pm
Forum: Quantum Numbers and The H-Atom
Topic: Lecture confusion in quantum numbers
Replies: 6
Views: 51

Re: Lecture confusion in quantum numbers

The px orbital is -1 for ml. There are three p sections (px, py, pz). Px corresponds to ml -1, py is ml 0 and pz is ml 3. Hope that helps. Looking at it visually on the diagram shown in lecture is helpful as well.
by Samantha Lee 1A
Wed Oct 21, 2020 9:35 pm
Forum: Administrative Questions and Class Announcements
Topic: Step Up Sessions
Replies: 71
Views: 4382

Re: Step Up Sessions

MIDTERM REVIEW SESSIONS - I saw on the class website that there is a tab for midterm review sessions. I was wondering if they are apart of step up sessions or if they are hosted by Dr. Lavelle at a different time/location. And, when will the review session be?
by Samantha Lee 1A
Wed Oct 21, 2020 11:11 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Applied to particles other than electrons
Replies: 5
Views: 21

Applied to particles other than electrons

Today's lecture talked a lot about how Heisenberg's equation applied to electrons. Does this equation also apply to neutrons and protons / other particles, or only electrons?
by Samantha Lee 1A
Tue Oct 20, 2020 10:02 am
Forum: Properties of Light
Topic: Tips to memorize wavelengths of the spectrum
Replies: 7
Views: 57

Tips to memorize wavelengths of the spectrum

I know we have to memorize the order of the spectrum (microwave --> gamma rays), but we also have to know the wavelengths of each one. Any tips on how to memorize that?
by Samantha Lee 1A
Mon Oct 19, 2020 11:26 am
Forum: Properties of Light
Topic: Difference between E=hv and E=hc/v?
Replies: 9
Views: 59

Re: Difference between E=hv and E=hc/v?

E = hv and E = hc/lambda will give you the same energy. There are used when you aren't given enough information to use the other equation. For example, if you are given h, c, and the wavelength (no frequency, v), then use E = hc/lambda. If you are given frequency, but not wavelength, use E = hv. Hop...
by Samantha Lee 1A
Fri Oct 16, 2020 10:53 am
Forum: Properties of Light
Topic: Examples of waves and particles of light
Replies: 2
Views: 32

Examples of waves and particles of light

Can someone please give some examples of when light acts like a wave v. when light acts like a particle (some examples we may see on an exam). Thank you
by Samantha Lee 1A
Thu Oct 15, 2020 11:00 am
Forum: Properties of Light
Topic: memorizing electromagnetic spectrum [ENDORSED]
Replies: 3
Views: 53

Re: memorizing electromagnetic spectrum [ENDORSED]

Yes - you have to know it. There are lots of mnemonics and songs to help you memorize it. Youtube and google are good resources for resources to memorize them. If you also use the information a lot, you will memorize it quickly.
by Samantha Lee 1A
Wed Oct 14, 2020 11:59 am
Forum: Properties of Electrons
Topic: Atomic Spectra
Replies: 5
Views: 53

Re: Atomic Spectra

When an electron is "excited", it moves to a higher energy state farther from the nucleus. The electron cannot stay excited for very long because it requires a lot of energy, so the energy moves back down to the ground state. The ground state is where the electrons that are not excited by ...
by Samantha Lee 1A
Tue Oct 13, 2020 10:39 am
Forum: Properties of Light
Topic: Increasing energy of photon
Replies: 6
Views: 55

Re: Increasing energy of photon

The equations that can be used is E=hv and E=(hc)/lambda. Remember to be in Joules. Sometimes it is given in eV or kJ and you need to be in J for energy, meters for wavelength (lambda) and 1/seconds for frequency (v). H is planck's constant and c is the speed of light. Hope this helps
by Samantha Lee 1A
Mon Oct 12, 2020 2:56 pm
Forum: Properties of Light
Topic: Quanta and Photons
Replies: 19
Views: 160

Re: Quanta and Photons

A variable that is quantized or discrete is a single unit. It is an individual unit (a whole number).
by Samantha Lee 1A
Thu Oct 08, 2020 2:49 pm
Forum: Balancing Chemical Reactions
Topic: States of Matter in Chemical Equations
Replies: 13
Views: 83

Re: States of Matter in Chemical Equations

The states of matter are REALLY important when it comes to chemical equations. When we start getting to other concepts, the states of matter could affect your answer. Also, it is a good idea to always put them down when writing the chemical equation as a habit now so you don't forget them later on w...
by Samantha Lee 1A
Wed Oct 07, 2020 10:59 am
Forum: Limiting Reactant Calculations
Topic: Limiting Reagents
Replies: 10
Views: 109

Re: Limiting Reagents

They are the same thing. The textbook likes to use Limiting Reactant and Dr. Lavelle likes to use Limiting Reagent in his slides but they mean the same thing.
by Samantha Lee 1A
Tue Oct 06, 2020 7:08 pm
Forum: Administrative Questions and Class Announcements
Topic: Posting during the weekends
Replies: 7
Views: 60

Re: Posting during the weekends

In office hours on Monday, Dr. Lavelle said a week ends on Sunday, so I would assume that weekends count for points and the tally (up to 5 posts a week) restart every Monday.
by Samantha Lee 1A
Mon Oct 05, 2020 3:30 pm
Forum: Administrative Questions and Class Announcements
Topic: Submitting HW on Sapling
Replies: 5
Views: 57

Submitting HW on Sapling

Do we have to submit the HW somehow or if we complete 100% of it we are done with that HW assignment?
by Samantha Lee 1A
Mon Oct 05, 2020 11:10 am
Forum: Molarity, Solutions, Dilutions
Topic: Serial Dilutions
Replies: 4
Views: 68

Serial Dilutions

I was wondering how we would use the equation M1V1 = M2V2 when it comes to serial dilutions. Do the moles of the solute remain the same and only the molarity gets diluted, or will the moles decrease as well?
by Samantha Lee 1A
Fri Oct 02, 2020 8:58 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Kinetic Energy Problem
Replies: 4
Views: 118

Kinetic Energy Problem

Hello - In one of the Audio-visual videos, there was a problem on how to calculate the kinetic energy using the Heisenberg Uncertainty equation. I was confused on how to address a problem like this in the future. Any advice?

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