Search found 53 matches
- Sun Dec 08, 2019 9:52 am
- Forum: Hybridization
- Topic: lone pairs in hybridization
- Replies: 6
- Views: 518
Re: lone pairs in hybridization
One lone pair would normally take up one hybridized orbital, just like the bonding pairs.
- Sun Dec 08, 2019 9:48 am
- Forum: Dipole Moments
- Topic: test 2 #6
- Replies: 2
- Views: 291
Re: test 2 #6
Professor said in class that only when all the surrounding atoms are the same, would the tetrahedral molecules be non-polar.
- Sun Dec 08, 2019 9:47 am
- Forum: Dipole Moments
- Topic: Cancelling dipole moments
- Replies: 11
- Views: 4521
Re: Cancelling dipole moments
You don't have to determine whether it is polar or not by trying to cancel every single dipole moment. If there is no lone pair on the central atom and all the other atoms are the same, it is a non-polar atom. If there are two opposite lone-pairs and all the other atoms are the same, it is probably ...
- Sun Dec 08, 2019 9:44 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: LDF
- Replies: 4
- Views: 435
Re: LDF
Yes. London forces exist among all molecules. A induced dipole occurs on non-polar molecules that got close to polar molecules. The uneven electronic distribution in unpolar molecules would change the distribution of electrons in non-polar molecules.
- Sun Dec 08, 2019 9:39 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Hydrogen
- Replies: 3
- Views: 316
Re: Hydrogen
Normally you would just count the number of bonds (double and triple count as one) in the molecule.
- Sun Nov 24, 2019 11:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Seesaw shape
- Replies: 5
- Views: 225
Seesaw shape
Can anyone please explain why the seesaw shape would occur? In what circumstance would it appear?
- Sun Nov 24, 2019 11:37 pm
- Forum: Trends in The Periodic Table
- Topic: Octet Expansion
- Replies: 5
- Views: 424
Re: Octet Expansion
Starting from period 3, elements have the chance to expand their octets. Because in period three, electron orbitals go up to 3d.
- Sun Nov 24, 2019 12:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Non-polar atoms with lone pairs
- Replies: 4
- Views: 252
Non-polar atoms with lone pairs
If a molecule has 1 lone pair, is it ever gonna be non-polar?
If it has 2 lone-pairs, can it be non-polar, since the lone pairs could possibly cancel each other?
If it has 3, 4, 5..., can it still be non-polar?
If it has 2 lone-pairs, can it be non-polar, since the lone pairs could possibly cancel each other?
If it has 3, 4, 5..., can it still be non-polar?
- Sun Nov 24, 2019 12:16 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Non-polar molecules with different non-central atoms
- Replies: 3
- Views: 196
Non-polar molecules with different non-central atoms
If a molecule has one central atom with no lone pairs, four other atoms with two of them being the same, and the other two being the same (central atom + 2 A atoms + 2 B atoms, five atoms in total in this molecule.), would it still be a non-polar molecule? In other words, even though we have two dif...
- Sun Nov 24, 2019 12:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent vs linear
- Replies: 56
- Views: 3893
Re: Bent vs linear
A molecule would be bent because it has lone pairs on the central atom. Lone pairs have very strong electronic repulsion, for which the other two atoms bonded to the central atom are repelled to be as far from the lone pair as possible.
- Sun Nov 17, 2019 6:08 pm
- Forum: Dipole Moments
- Topic: SCl4 Molecule
- Replies: 5
- Views: 893
Re: SCl4 Molecule
There is a lone pair on the S atom, which makes this a polar atom overall. The Cl atoms are not directly opposite from each other, and that's why their dipole moments don't cancel.
- Sun Nov 17, 2019 6:02 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR repulsion model
- Replies: 8
- Views: 533
Re: VSEPR repulsion model
Repulsion plays a large role. It determine both the general arrangement of the atoms in molecules and the specific angles between bonds. Repulsion makes it important that electron clouds are located as far from each other as possible.
- Sun Nov 17, 2019 5:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Dipole moment
- Replies: 5
- Views: 323
Dipole moment
Can anyone please explain what exactly is dipole moment again? Why is it called "moment"?
- Sun Nov 17, 2019 5:53 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: repulsion strength
- Replies: 5
- Views: 263
Re: repulsion strength
Lone pair and lone pair have the largest repulsion
Lone pair and bonding pair have the second largest repulsion
Bonding pair and bonding pair have the least repulsion
Lone pair and bonding pair have the second largest repulsion
Bonding pair and bonding pair have the least repulsion
- Fri Nov 15, 2019 1:27 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: How do we determine bond angles?
- Replies: 4
- Views: 232
How do we determine bond angles?
For example, in 2E problem 5, how do we know what is the angle for ClO2+ ?
- Fri Nov 15, 2019 12:53 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: 3F problem 3
- Replies: 3
- Views: 267
3F problem 3
For which of the following molecules will dipole–dipole interactions
be important: (a) CH4; (b) CH3Cl; (c) CH2Cl2; (d) CHCl3;
(e) CCl4?
Can anyone please explain this for me? I don't quite understand the differences between these for types of molecules.
be important: (a) CH4; (b) CH3Cl; (c) CH2Cl2; (d) CHCl3;
(e) CCl4?
Can anyone please explain this for me? I don't quite understand the differences between these for types of molecules.
- Fri Nov 15, 2019 12:45 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Why does SO2 molecules have dipole-dipole interations?
- Replies: 4
- Views: 2005
Why does SO2 molecules have dipole-dipole interations?
Are they polar molecules due to lone pairs?
- Fri Nov 15, 2019 12:42 am
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Does dipole-dipole force only exist among polar molecules?
- Replies: 9
- Views: 1191
- Thu Nov 07, 2019 1:05 pm
- Forum: Lewis Structures
- Topic: Exceptions to the Octet Rule Question
- Replies: 5
- Views: 563
Re: Exceptions to the Octet Rule Question
Any element in and after the third period could have exceptions. The way you deal with the exceptions while drawing Lewis structure is basically make each atom an octet firstm and then attach the extra electrons onto the "exception atoms".
- Thu Nov 07, 2019 1:02 pm
- Forum: Lewis Structures
- Topic: Does the shape that I draw the Lewis structure matter?
- Replies: 14
- Views: 918
Re: Does the shape that I draw the Lewis structure matter?
Currently, I don't think that it does, as we have not gone over the shape part yet.
- Thu Nov 07, 2019 1:00 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent and Ionic Bonds
- Replies: 6
- Views: 307
Re: Covalent and Ionic Bonds
I guess the most formal ways to explain them is looking at the differences between the electronegativity values for atoms that bond together. If two atoms have their electronegativity values differ by more than 2, they are more ionic. If less than 1.6, they are more covalent.
- Thu Nov 07, 2019 12:57 pm
- Forum: Ionic & Covalent Bonds
- Topic: C, N, O, and F
- Replies: 13
- Views: 576
Re: C, N, O, and F
Yes, I believe they have to follow the octet rule as they can only have valence electrons as many as eight. Formal charges definitely don't have to be 0, even though the formal charges that are close to 0 makes the molecule more stable.
- Thu Nov 07, 2019 12:54 pm
- Forum: Ionic & Covalent Bonds
- Topic: Why is the ionization energy of nitrogen higher than that of oxygen's?
- Replies: 11
- Views: 863
Re: Why is the ionization energy of nitrogen higher than that of oxygen's?
Draw the electronic configuration of the two atoms and you will see that Nitrogen has a half-full 2p shell. This makes it more stable than other unfull 2p shells.
- Thu Nov 07, 2019 12:51 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent character and ionic character
- Replies: 5
- Views: 316
Covalent character and ionic character
Can anyone please explain the difference plz?
- Sun Nov 03, 2019 11:03 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: When would 3d orbital be filled before the 4s orbital?
- Replies: 8
- Views: 445
When would 3d orbital be filled before the 4s orbital?
When would 3d orbitals be filled before the 4s orbital?
And similarly, when would 4d filled before 5s? 4f before 6s?
I am just kind of confused as for what exactly is the order in which we fill our electrons into the orbitals. Obviously, there are quite some exceptions.
And similarly, when would 4d filled before 5s? 4f before 6s?
I am just kind of confused as for what exactly is the order in which we fill our electrons into the orbitals. Obviously, there are quite some exceptions.
- Sat Nov 02, 2019 9:35 pm
- Forum: Ionic & Covalent Bonds
- Topic: The Lewis structure for the chlorite ion ClO2- (Cl atom, 2 oxygen atoms, and one negative charge)
- Replies: 1
- Views: 499
The Lewis structure for the chlorite ion ClO2- (Cl atom, 2 oxygen atoms, and one negative charge)
Seems like Cl is the central atom and two oxygen atoms are both connected to it. Oxygens only have 6 outer electrons, but in the lewis structure on the book, seems like one of the oxygen atom does not have any electrons contributed to covalent bonding? You can find it on page 80 (topic 2B). When wou...
- Sat Nov 02, 2019 9:27 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions in electronic configurations?
- Replies: 3
- Views: 234
Re: Exceptions in electronic configurations?
The exceptions to electron configurations are Chromium and Copper. Basically, in these two elements, you do not fill up the 4s shell first. Instead, you put one electron into the 4s shell and then move on to the 3d shell. So Cr's electron configuration is [Ar] 3d5 4s1 and Cu is [Ar] 3d10 4s1. The w...
- Sat Nov 02, 2019 9:05 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions in electronic configurations?
- Replies: 3
- Views: 234
Exceptions in electronic configurations?
Does anyone know which atoms are the exceptions for electronic configuation?
And why are they exceptions?
And why are they exceptions?
- Sat Nov 02, 2019 9:02 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 2A problem 5
- Replies: 2
- Views: 155
Re: 2A problem 5
The answer is [Ar]3d10 because even though the 4s block on the periodic table is seen before the 3d block, 3d is still a shell below 4s and therefor the 3d shell would fill up before you could add any electrons to the 4s orbital. Because Cu+ has 28 valence electrons and you know that it comes after...
- Sat Nov 02, 2019 8:33 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 2A problem 5
- Replies: 2
- Views: 155
2A problem 5
On the textbook, this problem asks us to write the electronic configuration of Cu+, Bi3+, Ga3+, and Tl3+. Except for Bi3+, the other three ions seem to be exceptions to the energy level rule. Can anyone explain why that happened? For example, for Cu+, I wrote [Ar]3d33p54s2, but the answer is [Ar]3d1...
- Sat Nov 02, 2019 4:01 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: How do we draw the electron configurations for transition metal atoms?
- Replies: 2
- Views: 140
How do we draw the electron configurations for transition metal atoms?
On the textbook 2A exercise 1, we are asked to write the valence electron of Sb, and the answer is 5. I thought that it would be 15. Can anyone explain why the valence electron is 5 and explain the electronic configuration of transition atoms in general?
- Sat Nov 02, 2019 2:27 pm
- Forum: Ionic & Covalent Bonds
- Topic: coulomb potential energy and Madelung constant, as well as lattice energy
- Replies: 4
- Views: 457
coulomb potential energy and Madelung constant, as well as lattice energy
Are we supposed to know these concepts and equations for midterms and finals?
If yes, can someone explain how the lattice energy works please?
If yes, can someone explain how the lattice energy works please?
- Sat Nov 02, 2019 1:55 pm
- Forum: Ionic & Covalent Bonds
- Topic: The net energy decrease when Na and Cl form NaCl
- Replies: 2
- Views: 147
The net energy decrease when Na and Cl form NaCl
On the book P72 (2A.3),it is said that "In summary, there is a net lowering of energy below that of the individual atoms, provided the net attraction between ions is greater than the energy needed to make them. The major contribution to the energy input is normally the ionization energy of the ...
- Sun Oct 27, 2019 3:29 pm
- Forum: Lewis Structures
- Topic: Lone pair
- Replies: 8
- Views: 351
Lone pair
Can anyone please explain what a lone pair is? Is it just the valence electrons that have not been used in bonding?
- Sun Oct 27, 2019 3:25 pm
- Forum: Electronegativity
- Topic: Difference between electronegativity, ionization energy, and electron affinity
- Replies: 5
- Views: 4482
Re: Difference between electronegativity, ionization energy, and electron affinity
Electronegativity is a property that describes how easily it is for an atom to gain electrons to form bonds.
Ionization energy is THE ENERGY it takes for an electron to leave an atom.
Electron affinity is also THE ENERGY that would be released when an electron is added to a neutral atom or molecule.
Ionization energy is THE ENERGY it takes for an electron to leave an atom.
Electron affinity is also THE ENERGY that would be released when an electron is added to a neutral atom or molecule.
- Sun Oct 27, 2019 3:15 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization and Electron Affinity
- Replies: 5
- Views: 304
Re: Ionization and Electron Affinity
Ionization energy represents the energy needed to REMOVE one electron from the atom, which is a representation of how easily the atom loses electrons. Electron affinity is the opposite. It measure how easily an atom GAINs electrons. The trends for these two properties are mostly opposite on the peri...
- Sun Oct 27, 2019 3:13 pm
- Forum: Ionic & Covalent Bonds
- Topic: Resonance
- Replies: 10
- Views: 364
Resonance
So if these is resonance for a specific molecule, does it mean that there are three slightly different structures that exist for this one molecule? Or it just means that we can write its Lewis structure in three different ways?
- Sun Oct 27, 2019 3:11 pm
- Forum: Ionic & Covalent Bonds
- Topic: Benzene's covalent bond
- Replies: 2
- Views: 173
Benzene's covalent bond
Can anyone explain again what's special about Benzene's chemical bonds? Is it a case of resonance?
- Sun Oct 20, 2019 9:16 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Summary of how to write electron configurations please
- Replies: 2
- Views: 100
Re: Summary of how to write electron configurations please
I will try to be as comprehensive as possible, but if I missed anything, please correct me :) 1. know how many electrons this specific atom has 2. know the order in which subshells are filled 3. know how many electrons a specific subshell can take, for example, s has one orbital and can take 2 elect...
- Sun Oct 20, 2019 9:07 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Why is 4s before 3d?
- Replies: 9
- Views: 881
Re: Why is 4s before 3d?
Because 4s has lower energy than 3d. There are some exceptions like this where higher energy level subshells are actually filled first.
- Sun Oct 20, 2019 11:56 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron configurations for Ni and Sc
- Replies: 1
- Views: 104
Electron configurations for Ni and Sc
In the lecture, professor wrote the two electron configuration:
Ni: [Ar]3d8 4s2
Sc: [Ar]3d1 4s2
Can anyone please explain why 3d is filled with 8 and 1 electron in these two cases?
Ni: [Ar]3d8 4s2
Sc: [Ar]3d1 4s2
Can anyone please explain why 3d is filled with 8 and 1 electron in these two cases?
- Sun Oct 20, 2019 11:52 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Exceptions for Electron Configuration
- Replies: 6
- Views: 195
Exceptions for Electron Configuration
In the lecture on Friday 10/18, professor mentioned how there exists EXCEPTIONS that half full d subshells and full d subshells have lower energy. Does anyone remember what this is exception to?
- Sun Oct 20, 2019 11:49 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: electrostatic attraction
- Replies: 1
- Views: 119
electrostatic attraction
Can anyone please explain what electrostatic potential energy is? Ane how would it affect the interaction of electrons and atoms?
- Sun Oct 20, 2019 11:39 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: The order in which subshells are filled
- Replies: 3
- Views: 96
The order in which subshells are filled
Can anyone please explain why some subshells in higher energy levels are filled earlier than those in lower energy levels?
- Sun Oct 20, 2019 11:36 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Orbitals with different levels of energy
- Replies: 1
- Views: 62
Orbitals with different levels of energy
I'm a little confused as to how we should write electron configurations. I know that subshells in lower energy levels are sometimes filled after the higher energy level subshells. But as professor Lavelle said, we should still write it from lower energy levels to higher energy levels and from s to p...
- Sun Oct 20, 2019 11:29 am
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Unpaired electrons
- Replies: 1
- Views: 33
Unpaired electrons
Can anybody please explain what unpaired electrons are? When would there be unpaired electrons?
- Thu Oct 17, 2019 9:52 pm
- Forum: Properties of Light
- Topic: atomic spectra module
- Replies: 1
- Views: 145
Re: atomic spectra module
First, you can calculate the wavelength. Since you know that one meter is composed of 1,650,763.73 wavelengths of radiation emitted by krypton-86, you can basically divide one meter by this number, and you get the length of one wavelength. In terms of region, you can just check the spectrum and see ...
- Thu Oct 17, 2019 9:47 pm
- Forum: Properties of Light
- Topic: Problem 1A.7
- Replies: 5
- Views: 212
Re: Problem 1A.7
A) Just use the equation c = wavelength * frequency. All light (including those that we cannot see like infrared and ultraviolet) have the same velosity, which is denoted by c, and it is equal to 3.0*10^8 m/s (this is not the more precise though, you might need to look up the precise value for preci...
- Thu Oct 17, 2019 9:42 pm
- Forum: Properties of Electrons
- Topic: Wave Function
- Replies: 5
- Views: 218
Wave Function
Can anyone please explain the wave function to me again? I'm still kind of confused as for how the function is used. Does the wave function correspond to the the s, p, d ... orbitals we are talking about in the lecture?
- Wed Oct 16, 2019 9:32 pm
- Forum: Properties of Electrons
- Topic: The wave property of electrons [ENDORSED]
- Replies: 2
- Views: 113
The wave property of electrons [ENDORSED]
Could anyone explain the wave property of electrons again?
Why does electrons have wave-like property? I know that through the diffraction experiment, we have proven that electrons have wavelike properties, but why could this experiment show this?
Thank you!
Why does electrons have wave-like property? I know that through the diffraction experiment, we have proven that electrons have wavelike properties, but why could this experiment show this?
Thank you!
- Wed Oct 16, 2019 9:27 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: What does the "x" indicate in (i.e.) the 2px state? [ENDORSED]
- Replies: 5
- Views: 354
Re: What does the "x" indicate in (i.e.) the 2px state? [ENDORSED]
I believe that x just means the x plane. Because the orbitals are 3D models, so we have x, y, and z planes. There could be multiple p orbitals in one atom, and they are normally arranged in different directions. To distinguish them, we use x to indicate the one that goes along the direction of the x...
- Tue Oct 15, 2019 9:59 pm
- Forum: DeBroglie Equation
- Topic: Energy = mv^2
- Replies: 2
- Views: 134
Energy = mv^2
Hi! I remember in class professor Lavelle talked about how we could derive E = mv^2 from E = mc^2. I'm just not entirely sure about this equation. Is E = mv^2 applicable in any cases? For example, if I want to calculate the total energy of a moving baseball, can I use this equation? Also, since Kine...
- Tue Oct 15, 2019 9:32 pm
- Forum: DeBroglie Equation
- Topic: Calculating Wavelength
- Replies: 5
- Views: 273
Re: Calculating Wavelength
Hi! I haven't done this problem before but I think what it means is that after you calculate the difference of the wavelengths (between protons and neutrons), you need to then calculate how much of the wavelength of neutron does this difference in wavelengths take up. Namely, diff divide by waveleng...