Search found 31 matches
- Sun Jun 03, 2018 10:56 pm
- Forum: Hybridization
- Topic: Lone Pairs
- Replies: 5
- Views: 632
Re: Lone Pairs
I think hybridization changes if the lone pairs are attached to the central atom, but that's it.
- Sun Jun 03, 2018 10:53 pm
- Forum: Hybridization
- Topic: Hybridization Notation
- Replies: 3
- Views: 392
Re: Hybridization Notation
I don't think that you have to follow the textbook's version of the hybridization notation, and just use the notation that Dr. Lavelle uses. He has taught other concepts and equation that were not per the textbook, and has advised us to use his method that he teaches in class.
- Sun Jun 03, 2018 10:48 pm
- Forum: Hybridization
- Topic: Clarification
- Replies: 4
- Views: 601
Re: Clarification
I believe that it's trying to let you know that the same hybridization concepts apply with the molecules you mentioned; no special rules.
- Tue May 29, 2018 4:26 pm
- Forum: Bond Lengths & Energies
- Topic: HW question 4.1
- Replies: 5
- Views: 672
Re: HW question 4.1
Both the number of bonds and number of lone pairs take part in determining the shape of the molecule.
- Tue May 29, 2018 4:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 4.1
- Replies: 5
- Views: 656
Re: 4.1
Molecules can have lone pairs, and can also end up affecting the shape as well.
- Tue May 29, 2018 4:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: single electron and shape
- Replies: 3
- Views: 344
Re: single electron and shape
I don't think a single electron is enough to change the shape of a molecule, which is why only lone pairs are taken into account of molecular shape.
- Tue May 22, 2018 12:33 pm
- Forum: Bond Lengths & Energies
- Topic: Test 3 Material Question
- Replies: 3
- Views: 551
Re: Test 3 Material Question
You should know how to draw Lewis structures of molecules, including the special cases like expanded octets and resonance, as well as ionic vs. covalent bonds, and bond length & strength.
- Tue May 22, 2018 12:19 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Stable lewis structures
- Replies: 2
- Views: 392
Re: Stable lewis structures
By adding another bond, you are able to make the formal charge of the molecule closer to 0, making it more stable. To help you figure out whether two atoms need another bond, just calculate the formal charge on each atom, and keep adding bonds wherever it is necessary in order to make the formal cha...
- Tue May 22, 2018 12:15 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 4
- Views: 895
Re: Bond Angles
I also looked up some information on the correlation of amount of bounds and the bond angles, so I also know that bond angles are affected by the number of bonds. However, I don't think that this is something we need to focus on too much because the syllabus does not necessarily mention this concept.
- Tue May 15, 2018 5:39 pm
- Forum: Resonance Structures
- Topic: CN- Resonance structures [ENDORSED]
- Replies: 2
- Views: 1378
Re: CN- Resonance structures [ENDORSED]
Yes, that is allowed! Another resonance structure with the same formal charge can be a triple bond with a lone pair for each element.
- Tue May 15, 2018 5:32 pm
- Forum: Resonance Structures
- Topic: How do Resonance Structures Work?
- Replies: 4
- Views: 631
Re: How do Resonance Structures Work?
Although all resonance structures are acceptable forms of a Lewis structure, you would need to draw out all the possible resonance structure (if asked to), and indicate that they are of resonance by a double ended arrow: <->
- Tue May 15, 2018 5:30 pm
- Forum: Lewis Structures
- Topic: Order of Dots
- Replies: 11
- Views: 1266
Re: Order of Dots
I don't think that you have to fill the valence electrons in a specific order, all you need to do is make sure you're filling them in symmetrically. For example, if you had a molecule that had the following structure ( E - H - E ), and you had 8 valence electrons to fill, you would do have to fill ...
- Tue May 08, 2018 10:24 am
- Forum: Trends in The Periodic Table
- Topic: Homework Problem 2.59 [ENDORSED]
- Replies: 1
- Views: 320
Re: Homework Problem 2.59 [ENDORSED]
Because they all have the same number of valence electrons at this point, you would take into consideration how many protons each element has. We know that the more protons there are, the smaller the radius will be because the electrons are more attracted to the nucleus. Because Cl has the most numb...
- Tue May 08, 2018 10:15 am
- Forum: Ionic & Covalent Bonds
- Topic: Memorization of Electronegativity
- Replies: 6
- Views: 987
Re: Memorization of Electronegativity
In one of the review sessions I attended, some of his previous midterm questions asked which of the 2 elements had a higher/lower electron affinity, atomic radii, etc. Therefore, you don't need to know specific values, just general trends.
- Tue May 08, 2018 10:11 am
- Forum: Lewis Structures
- Topic: Order of Dots
- Replies: 11
- Views: 1266
Re: Order of Dots
I don't think that you have to fill the valence electrons in a specific order, all you need to do is make sure you're filling them in symmetrically. For example, if you had a molecule that had the following structure ( E - H - E ), and you had 8 valence electrons to fill, you would do have to fill 4...
- Mon Apr 30, 2018 10:37 pm
- Forum: Trends in The Periodic Table
- Topic: atomic mass
- Replies: 3
- Views: 306
Re: atomic mass
Another trend that follows a similar line of logic is electronegativity. Electronegativty increases from bottom to top, and from left to right in relation to the periodic table.
- Mon Apr 30, 2018 10:33 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Electron Configuration form
- Replies: 4
- Views: 482
Re: Electron Configuration form
However, there are 2 exceptions that were mentioned in lecture where you can write the shorthand for the electron configurations, but they do not follow the typical rule when it comes to writing their electron configurations. CHROMIUM (Cr): [Ar] 3d5 4s1, not [Ar] 3d4 4s2 COPPER (Cu): [Ar] 3d10 4s1, ...
- Mon Apr 30, 2018 10:26 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals in Relation to Periodic Table
- Replies: 2
- Views: 270
Orbitals in Relation to Periodic Table
How exactly do the orbitals correlate to the blocks on the periodic table? I know that there is an s-, p-, d-, and f- block on the periodic table, as well as the s-, p-, d-, f- orbitals, but I just can't seem to see how both are related to eachother.
- Tue Apr 24, 2018 4:06 pm
- Forum: Properties of Light
- Topic: Test 2 Material
- Replies: 12
- Views: 1197
Re: Test 2 Material
Should we understand the ranges of wavelengths of light? like the specific ranges of wavelength (visible light, UV,etc...) because I know some module questions asked that and I don't know the range off the top of my head. thanks! Our TA told us to be familiar with the increasing or decreasing order...
- Tue Apr 24, 2018 4:00 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation
- Replies: 4
- Views: 549
Re: Rydberg Equation
The actual Rydberg's formula is the one that you typed in the latter half of your question. The steps that Dr. Lavelle took was just the step by step version of the formula, then used to find wavelength.
- Tue Apr 24, 2018 3:53 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals as states
- Replies: 2
- Views: 235
Re: Orbitals as states
I was also confused when he said that orbitals couldn't be seen as hotel rooms, because each orbital contains electrons which stay in their respective orbital. Is there a different situation that Dr. Lavelle was talking about when he told us not to look at the orbitals as "hotel rooms"?
- Mon Apr 16, 2018 9:19 am
- Forum: Properties of Light
- Topic: still don't uderrsatnd what a photon is [ENDORSED]
- Replies: 20
- Views: 1440
Re: still don't uderrsatnd what a photon is [ENDORSED]
A photon is basically a wavelength of light, and is typically portrayed as a squiggly line coming from the sun in many diagrams that involve a photon.
- Mon Apr 16, 2018 9:15 am
- Forum: Properties of Light
- Topic: Photon units? [ENDORSED]
- Replies: 4
- Views: 591
Re: Photon units? [ENDORSED]
I believe the units for a photon is in terms of joules (J).
- Mon Apr 16, 2018 9:13 am
- Forum: Properties of Light
- Topic: Speed of light constant
- Replies: 5
- Views: 485
Re: Speed of light constant
Taizha 1C wrote:Do we need to memorize the speed of light in different conditions for the exam?
I believe that such constants will be given to us on the exam.
- Wed Apr 11, 2018 9:47 am
- Forum: Properties of Light
- Topic: Value of Speed of Light** (Shoutout to Dr. Lavelle for calling me out in lecture today) [ENDORSED]
- Replies: 4
- Views: 580
Value of Speed of Light** (Shoutout to Dr. Lavelle for calling me out in lecture today) [ENDORSED]
In lecture on Monday, Dr. Lavelle briefly introduced the equation that frequency x wavelength = speed of light. What is the value of speed of light? I googled it, and it spit back 299,792,458 m/s. Do we use this insanely large value, or do we use scientific notation of this value? Is the latter, wha...
- Sun Apr 08, 2018 9:56 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: What do the coefficients/subscripts represent [ENDORSED]
- Replies: 7
- Views: 1534
Re: What do the coefficients/subscripts represent [ENDORSED]
In a single H20 molecule, there are 2 atoms of hydrogen. However, the coefficient 4 in front of the H20 means there are 4 H20 molecules. So, there are 8 total atoms of hydrogen in the 4H20 molecules (2 atoms of hydrogen per 1 H20 molecule x 4 H20 molecules = 8 atoms of hydrogen atoms).
- Sun Apr 08, 2018 9:50 pm
- Forum: Limiting Reactant Calculations
- Topic: Actual Yield [ENDORSED]
- Replies: 3
- Views: 538
Re: Actual Yield [ENDORSED]
The actual yield is a part of many human errors and natural occurrences, so there is no accurate way to measure the actual yield. Most of the time, we should only be asked to calculate for the theoretical yield.
- Sun Apr 08, 2018 9:47 pm
- Forum: Empirical & Molecular Formulas
- Topic: Periodic Table Memorization [ENDORSED]
- Replies: 8
- Views: 861
Re: Periodic Table Memorization [ENDORSED]
Although we don't need have to memorize the periodic table, I find it useful to memorize the atomic masses of some common elements, such as hydrogen and oxygen, to save time in some calculations.
- Sun Apr 08, 2018 9:43 pm
- Forum: Balancing Chemical Reactions
- Topic: Memorizing the charges of ions
- Replies: 3
- Views: 437
Re: Memorizing the charges of ions
My TA suggested that it is expected of us to know the some basic ions, polyatomic ions specifically, which can be referenced under the Fundamental section in the textbook.
- Sun Apr 08, 2018 9:40 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Variables
- Replies: 5
- Views: 545
Re: Variables
Another is mmol, which signifies millimoles.
- Sun Apr 08, 2018 9:37 pm
- Forum: Significant Figures
- Topic: Why are sig figs important?
- Replies: 13
- Views: 16200
Why are sig figs important?
I understand how the concept of significant figures work, but I just can't grasp why it is reiterated that we use them in chemistry related numbers. What is the purpose of significant figures?