Search found 36 matches

by Bianca Nguyen 1B
Sun Jun 10, 2018 10:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: sigma and pi bond
Replies: 2
Views: 112

Re: sigma and pi bond

A sigma bond is formed when 2 orbitals overlap end to end. A pi bond is formed when 2 orbitals overlap side to side. Pi bonds overlap with more surface area, so the bond is stronger. A pi bond will be 2 parallel p orbitals overlapping while a sigma bond will be any other orbitals overlapping. There ...
by Bianca Nguyen 1B
Sun Jun 10, 2018 10:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar/nonpolar
Replies: 3
Views: 96

Re: polar/nonpolar

To give examples, CCl4 is a nonpolar molecule because although it has 4 dipole moments all going towards the Cls, the dipole moments cancel out due to the symmetry of the molecule. BUT, if you replace two of the Cl atoms in the molecule with Br atoms, making CBr2Cl2, the new molecule is polar becaus...
by Bianca Nguyen 1B
Sun Jun 10, 2018 10:34 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Sigma vs Pi Bonds
Replies: 4
Views: 195

Re: Sigma vs Pi Bonds

I believe so, but we might also be tested on the composition of each bond for ex. σ (H 1s, C 2sp^2) would be the composition of a C-H bond
by Bianca Nguyen 1B
Sun Jun 03, 2018 11:33 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Significance of Coordination Number?
Replies: 7
Views: 158

Re: Significance of Coordination Number?

I would guess that it would help with naming the shape on the exam, since Dr. Lavelle said naming of coordination compounds would not be tested.
by Bianca Nguyen 1B
Sun Jun 03, 2018 11:30 pm
Forum: Naming
Topic: Coordination Compounds
Replies: 3
Views: 177

Re: Coordination Compounds

A coordination sphere is made up from the ligands directly attached to the central ion or metal atom. A coordination number tells us the number of bonds the central metal is bonded to. A coordination compound is biologically significant as seen in the function of hemoglobin and when cisplatin forms ...
by Bianca Nguyen 1B
Sun Jun 03, 2018 11:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Radical
Replies: 4
Views: 87

Re: Radical

I think you’re right Mariah. Even though a radical would still be counted as a region of electron density just like a lone pair, because there is only one electron, it won’t repel the shared electrons as much as a lone pair would, therefore resulting in a larger bond angle.
by Bianca Nguyen 1B
Tue May 22, 2018 12:47 am
Forum: Lewis Structures
Topic: Carbon Monoxide Lewis Structure
Replies: 3
Views: 122

Re: Carbon Monoxide Lewis Structure

Hi Elizabeth, You’re right that carbon only has 4 valence electrons, but oxygen has 6. So in order to give both atoms an octet, one of the three bonds is going to have both electrons coming from oxygen. This can be kind of confusing to think about, but as long as you just remember that both atoms ar...
by Bianca Nguyen 1B
Tue May 22, 2018 12:39 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: HW 3.83
Replies: 6
Views: 467

Re: HW 3.83

Answering Madeleine’s question: N3- and O2- are isoelectronic or have the same amount of electrons, which is 10. So to figure out which one is bigger, we have to look at the amount of protons. N3- has 7 protons while O2- has 8 protons, therefore O2- is going to have a smaller ionic radius because th...
by Bianca Nguyen 1B
Mon May 21, 2018 10:43 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge in (S2CO)2-
Replies: 3
Views: 438

Re: Formal charge in (S2CO)2-

I thought putting a negative formal charge on more electronegative atoms made sense, since they’re pulling electrons toward them. In this case, I think that the answer key is right. O is more electronegative than S, so there should be a -1 charge on the O and a -1 charge on the S rather than a -1 ch...
by Bianca Nguyen 1B
Mon May 21, 2018 10:22 pm
Forum: Lewis Structures
Topic: 3.33 and ionization energy
Replies: 3
Views: 97

Re: 3.33 and ionization energy

O may have a lower ionization energy than N, but it has a higher electronegativity than N, thus making N the central atom as it is the least electronegative. In the beginning of Chapter 3, the book said that we would say the atom with the “lowest ionization energy” is the center atom, but later on i...
by Bianca Nguyen 1B
Sun May 20, 2018 11:32 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character?
Replies: 3
Views: 124

Re: Covalent Character?

I think that what we mean when we say that an ionic bond has covalent character is that the electrons are more likely to be pulled into the bonding region where they can be shared between the two nuclei. An ionic bond with more covalent character will have more distorted electrons (meaning that the ...
by Bianca Nguyen 1B
Sun May 20, 2018 11:20 pm
Forum: Properties of Electrons
Topic: Midterm #2 question 4a,b
Replies: 5
Views: 211

Re: Midterm #2 question 4a,b

Miya is right. I believe the cutoff is 10^-18 for the wavelength. If the wavelength is smaller than that, as is the wavelength for objects such as a ball or a car, then wavelength properties cannot be detected, and that is why we say that these objects do not have wavelength properties.
by Bianca Nguyen 1B
Sun May 20, 2018 11:15 pm
Forum: Dipole Moments
Topic: Meaning of a dipole
Replies: 7
Views: 123

Re: Meaning of a dipole

Answering Victoria’s question, if there is a greater dipole moment, then yes the molecule has a stronger ionic bond between its atoms. I would think that its potential energy wouldn’t necessarily be greater, as the weakest bond, Van Der Waals, has the greatest potential energy out of all bonds/inter...
by Bianca Nguyen 1B
Sun May 13, 2018 10:47 pm
Forum: Formal Charge and Oxidation Numbers
Topic: FORMAL CHARGE
Replies: 9
Views: 183

Re: FORMAL CHARGE

Yes, I think they are the dots!
by Bianca Nguyen 1B
Sun May 13, 2018 10:46 pm
Forum: Formal Charge and Oxidation Numbers
Topic: FORMAL CHARGE
Replies: 9
Views: 183

Re: FORMAL CHARGE

Also, I believe the amount of lone pair electrons will be the electrons on an atom that are not shared through bonds.
by Bianca Nguyen 1B
Sun May 13, 2018 10:41 pm
Forum: Electronegativity
Topic: Electronegativity vs. Electron affinity
Replies: 7
Views: 210

Re: Electronegativity vs. Electron affinity

I think an exception for this though would be hydrogen, as it is never a central atom since it can only share 1 electron
by Bianca Nguyen 1B
Tue May 08, 2018 12:51 am
Forum: Einstein Equation
Topic: Question on Midterm
Replies: 7
Views: 259

Re: Question on Midterm

Pretty sure we use whatever is given to us on the Constants and Equations sheet on the front. Thus, for Plank’s constant we’d use 6.62608 x 10^-34
by Bianca Nguyen 1B
Tue May 08, 2018 12:43 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 2.55 - what does valence-shell configuration mean?
Replies: 3
Views: 203

Re: 2.55 - what does valence-shell configuration mean?

A shell basically represents a principle quantum number. You can think of it as n=shell, l=subshell, and ml=orbitals of a subshell. For every period in the periodic table, the s and p block will always be in the same shell or have the same principle quantum number (for ex., 2s and 2p, 3s and 3p). So...
by Bianca Nguyen 1B
Sat May 05, 2018 3:35 pm
Forum: Trends in The Periodic Table
Topic: 2.67 part c) and d) [ENDORSED]
Replies: 5
Views: 130

2.67 part c) and d) [ENDORSED]

In 2.67 part c), the solutions manual says that chlorine has a higher electron affinity than bromine and in part d), it says that lithium has a higher electron affinity than sodium. I just wanted to make sure my reasoning for this is correct. Is it because chlorine and lithium have smaller atomic ra...
by Bianca Nguyen 1B
Sat May 05, 2018 3:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Chapter 2 HW: #39 [ENDORSED]
Replies: 7
Views: 1174

Re: Chapter 2 HW: #39 [ENDORSED]

B) violates ground state expectations because of Hund’s rule. You must fill up electrons parallel to each other first (All up or all down first) because of electron repulsion, but I’m not completely sure what electron repulsion has to do with them all having to be parallel since they’re in different...
by Bianca Nguyen 1B
Sat May 05, 2018 3:12 pm
Forum: Trends in The Periodic Table
Topic: Practice midterm 6d
Replies: 2
Views: 57

Re: Practice midterm 6d

O and N are flipped because of half-shell stability. N does not want to lose an electron because all of its p orbitals are filled with an electron and they are parallel to each other. It is easier to remove an electron from O because it will have half-shell stability when you remove an electron. I’m...
by Bianca Nguyen 1B
Sat May 05, 2018 1:37 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.43
Replies: 7
Views: 133

Re: 2.43

Hi Joanna! I also had this same question about part e) and am not completely sure but this is what Chem_Mod said on another post regarding this: “I believe that the reason that tungsten does not get a half filled shell is because it is in a lower row of the d-block. Additionally, it has the availabl...
by Bianca Nguyen 1B
Sun Apr 29, 2018 11:24 pm
Forum: Trends in The Periodic Table
Topic: s, p, d, f
Replies: 16
Views: 295

Re: s, p, d, f

I would guess that a possible problem could be giving you something like “4d” and asking you to write out or choose the correct possible four quantum numbers (n, l, ml, and ms) that 4d could have
by Bianca Nguyen 1B
Sun Apr 29, 2018 11:21 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Parallel vs Paired Electrons
Replies: 2
Views: 64

Re: Parallel vs Paired Electrons

When two electrons are parallel, both will be having the same spin or both going up/going down. When two electrons are paired, they will have opposite spins, one going up and one going down.
by Bianca Nguyen 1B
Sun Apr 29, 2018 11:08 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: orbitals/lobes
Replies: 3
Views: 126

Re: orbitals/lobes

I think that if you can draw the general shapes of the orbitals you should be good, such as what an s, p, or d orbital would look like on axes.
by Bianca Nguyen 1B
Sun Apr 22, 2018 2:30 pm
Forum: DeBroglie Equation
Topic: HW 1.33
Replies: 12
Views: 356

Re: HW 1.33

The frequency 2.5 x 10^16 Hz was given to you in part b of the question
by Bianca Nguyen 1B
Sun Apr 22, 2018 2:20 pm
Forum: Properties of Light
Topic: HW #1.65
Replies: 2
Views: 66

Re: HW #1.65

I looked at the chart in the book. Not sure whether something like this will be asked of us on a test. In that case, I think the only way to know is just through memorization.
by Bianca Nguyen 1B
Sun Apr 22, 2018 2:40 am
Forum: Photoelectric Effect
Topic: Energy levels
Replies: 7
Views: 180

Re: Energy levels

I get that dropping from energy level n=2 to n=1 has the biggest energy difference, but why, as someone stated, does a drop from n=2 to n=1 have more energy than a drop from n=4 to n=1?
by Bianca Nguyen 1B
Sun Apr 22, 2018 2:33 am
Forum: Properties of Electrons
Topic: 1.57 [ENDORSED]
Replies: 2
Views: 107

Re: 1.57 [ENDORSED]

To answer your question anyway, the next line in the series would be n2=7 because 656.3 corresponds to n1=2 to n2=3, 486.1 corresponds to n1=2 to n2=4, 434.0 corresponds to n1=2 to n2=5, and 410.2 corresponds to n1=2 to n2=6.
by Bianca Nguyen 1B
Sun Apr 15, 2018 11:44 pm
Forum: Photoelectric Effect
Topic: E(photon)>or=E(energy remove e-) [ENDORSED]
Replies: 2
Views: 77

Re: E(photon)>or=E(energy remove e-) [ENDORSED]

Basically, in the photoelectric effect, light is not acting like a classical wave, where the bigger or more intense the wave is, the more energy it has. So increasing the intensity of light does not add to the energy of photons. Rather the energy of a photon is proportional to its frequency, so even...
by Bianca Nguyen 1B
Sun Apr 15, 2018 4:12 pm
Forum: Photoelectric Effect
Topic: What is a vacuum?
Replies: 7
Views: 183

Re: What is a vacuum?

To add to that, the photoelectric experiment must be done in a vacuum so the electrons do not collide with random molecules in the air like CO2 for example
by Bianca Nguyen 1B
Mon Apr 09, 2018 9:47 pm
Forum: Empirical & Molecular Formulas
Topic: Worksheet Problem #4 [ENDORSED]
Replies: 2
Views: 287

Re: Worksheet Problem #4 [ENDORSED]

Remember that there are 2 oxygen atoms in O2. This means that the molar mass of O must be multiplied by 2 in order to get the molar mass of O2. So 16 g/mol of O x 2 is 32 g/mol, which is indeed the molar mass of O2.
by Bianca Nguyen 1B
Mon Apr 09, 2018 12:47 am
Forum: Limiting Reactant Calculations
Topic: M.7 (B)
Replies: 1
Views: 82

Re: M.7 (B)

Hi! Either method can be used to find the limiting reactant, which will be magnesium. However, since this problem is asking for the mass of boron that will be produced, the method used by the solution manual will find both the limiting reactant AND the mass of boron produced in one single calculatio...
by Bianca Nguyen 1B
Fri Apr 06, 2018 3:08 pm
Forum: SI Units, Unit Conversions
Topic: What is the notation for molar mass?
Replies: 15
Views: 419

Re: What is the notation for molar mass?

I believe the notation for molar mass is M
by Bianca Nguyen 1B
Fri Apr 06, 2018 1:30 pm
Forum: SI Units, Unit Conversions
Topic: Using units in calculations [ENDORSED]
Replies: 4
Views: 124

Re: Using units in calculations [ENDORSED]

Hi! I believe that as long as your final answer includes the correct units, then doing the calculations without units should be fine, BUT I definitely agree with Andrew on this one as including units in your calculations really aids in your understanding as well as the grader’s in how you got from P...
by Bianca Nguyen 1B
Fri Apr 06, 2018 1:16 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Which mass of oxygen should be used? [ENDORSED]
Replies: 23
Views: 804

Re: Which mass of oxygen should be used? [ENDORSED]

I believe that using 16 grams/mole for the mass of oxygen should be okay as Dr. Lavelle has done this in his example problems for the Audio-Visual Focus Topics as well as during lectures. I feel that using this shouldn’t affect your answer by much and should still allow you to receive full credit bu...

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