Search found 31 matches
- Mon Jun 04, 2018 7:24 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Outlining Steps for Determining Shape
- Replies: 1
- Views: 161
Outlining Steps for Determining Shape
Can someone outline the steps for determining the molecular and VSEPR shape? Like, how one should go about solving a problem when asked on an exam.
- Mon Jun 04, 2018 7:21 pm
- Forum: Hybridization
- Topic: basics of hybridization
- Replies: 18
- Views: 1292
Re: basics of hybridization
Hybridization is the concept of mixing atomic orbitals into new hybrid orbitals suitable for the pairing of electrons to form chemical bonds in the valence bond theory. The hybrid orbitals allow one to explain the molecular geometry and atomic bonding properties.
- Mon Jun 04, 2018 7:13 pm
- Forum: Conjugate Acids & Bases
- Topic: Oxoacids
- Replies: 5
- Views: 509
Re: Oxoacids
Adding on to what other students said, an oxoacid is an acid that contains oxygen, one other element, has at least one hydrogen bonded to the oxygen, and forms an ion by the loss of one or more protons. As stated above, acid strength increases when the central atom stays the same and as the number o...
- Thu May 31, 2018 12:30 pm
- Forum: Hybridization
- Topic: σ bonds
- Replies: 9
- Views: 483
Re: σ bonds
To add on, a sigma bond is a covalent bond resulting from the formation of a molecular orbital by the end-to-end overlap of atomic orbitals. These overlaps can occur between s-s, p-p, s-p
- Thu May 31, 2018 12:28 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR confusion
- Replies: 8
- Views: 690
Re: VSEPR confusion
To add on to what others said, VSEPR is used as a model in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.
- Thu May 31, 2018 12:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Double bond
- Replies: 3
- Views: 216
Re: Double bond
A pi bond is a covalent bond that results from the formation of a molecular orbital by side-to-side overlap of atomic orbitals along a plane perpendicular to a line. A double bond actually has one sigma and one pi bond.
- Sat May 26, 2018 5:14 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 4
- Views: 398
Re: Bond Angles
I also was looking up more information and I found that bond angles are affected the three factors: state of hybridization of central atom, lone pair repulsion, and electronegativity. Lone pair of electrons at the central atom always try to repel the shared pair of electrons, thus, bonds are slightl...
- Sat May 26, 2018 5:10 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar & Nonpolar
- Replies: 3
- Views: 246
Re: Polar & Nonpolar
In addition, we learned in class on Friday that a polar molecule must have polar bonds with dipoles that do not cancel and that a non polar molecule must have zero electric dipole moment which is possible if it contains non polar bonds or polar bonds with dipoles that cancel.
- Sat May 26, 2018 5:05 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polar Bonds versus non polar bonds
- Replies: 2
- Views: 193
Re: Polar Bonds versus non polar bonds
For determining whether a molecule is polar or not, you need to look at the dipole moments. If the dipole moments are going in opposite directions and cancel each other out then it is non polar. If the dipoles do not cancel it is a polar molecule. Dipole moments occur when there is a separation in c...
- Wed May 16, 2018 5:40 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: formal charge
- Replies: 11
- Views: 748
Re: formal charge
Formal charge can be calculated by looking at the number of electrons an atom wants and then subtracting each electron in lone pairs surrounding the atom and any electrons bonded (1 for each line in the lewis structure). In addition, the formula Dr. Lavelle stated in class was FC=V-(L+(S/2)).
- Wed May 16, 2018 5:36 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: FORMAL CHARGE
- Replies: 9
- Views: 540
Re: FORMAL CHARGE
The lines represent a bond between two atoms. Drawing a line on atom to represent a lone pair would not represent what the structure actually looks like since there is no bond. So when drawing lone pairs, just use the dots.
- Wed May 16, 2018 5:33 pm
- Forum: Bond Lengths & Energies
- Topic: Double Bond vs Triple Bond
- Replies: 7
- Views: 836
Re: Double Bond vs Triple Bond
I think you look at the formal charge like the student above stated, but also you can look at the number of electrons total and make sure whether you use a double bond and lone pair versus a triple bond that it still includes all the electrons as well as the formal charge.
- Sat May 12, 2018 7:06 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal charges and full valence shells
- Replies: 3
- Views: 305
Re: Formal charges and full valence shells
The formal charge is the difference between the number of valence electrons "belonging" to the bonded atom and those in the full valence shell. And, no the formal charge is not always 0, but that is when it has the lowest energy.
- Sat May 12, 2018 7:02 pm
- Forum: Octet Exceptions
- Topic: Octet fule in forming compounds
- Replies: 2
- Views: 233
Re: Octet fule in forming compounds
As the person above stated, calcium has two valence electrons (from the 4s orbital) that is must lose to have a complete octet. When it does this, it will behave like the atom Argon.
- Sat May 12, 2018 6:53 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Number & Bonds
- Replies: 6
- Views: 365
Re: Oxidation Number & Bonds
Yup! I think the oxidation numbers are essentially a way to keep track of how many electrons an atom has, thus, depending on the other atoms involved.
- Tue May 01, 2018 10:02 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Hund's Rule [ENDORSED]
- Replies: 6
- Views: 498
Re: Hund's Rule [ENDORSED]
Another way to think of Hund's Rule is thinking about how people sit on a school bus. People are more likely to sit in a seat by themselves before sitting next to someone else. Electrons in orbitals act the same way. There will not be paired electrons until each one occupies one spot in an orbital.
- Tue May 01, 2018 9:58 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 2.43
- Replies: 7
- Views: 4922
Re: 2.43
I agree with what was stated above. I think it follows the exceptions discussed in class about how a full 3d orbital, d^10, has a lower energy than the 4s orbital and how the electrons occupy the lower energy state first before filling the 4s orbital in this case.
- Tue May 01, 2018 9:52 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Zeff
- Replies: 1
- Views: 157
Re: Zeff
Zeff is notation for the effective nuclear charge. In the textbook, it discusses how electrons are attracted to the nucleus, but also repelled by other electrons present. As a result, it is less tightly bound to the nucleus than it would be if other electrons were absent. Thus, each electron is shie...
- Thu Apr 26, 2018 12:13 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Planes [ENDORSED]
- Replies: 6
- Views: 394
Re: Nodal Planes [ENDORSED]
I agree with the student above, additionally, the nodal plane is such a plane that does no intersect the associated orbital at any point, therefore, a low probability of finding an electron there.
- Thu Apr 26, 2018 12:04 pm
- Forum: DeBroglie Equation
- Topic: When to use DeBroglie or Ek equation
- Replies: 7
- Views: 460
Re: When to use DeBroglie or Ek equation
In addition to what everyone said, think about the context of the problem. You typically use the kinetic energy equation for the photoelectric effect and a situation describing it whereas the DeBroglie equation relates a moving particle's wavelength to its momentum, mass*velocity.
- Thu Apr 26, 2018 11:56 am
- Forum: Photoelectric Effect
- Topic: calculating the number of photons
- Replies: 2
- Views: 183
Re: calculating the number of photons
By using E=hv which is the quantization of electromagnetic radiation and the speed of light equation where c=lambda*v you are finding the photon energy and since you know the total energy for 2 seconds which is 64J, by dividing the total energy generated by the lamp and the energy per photon you get...
- Thu Apr 19, 2018 11:31 am
- Forum: Empirical & Molecular Formulas
- Topic: empirical vs molecular
- Replies: 5
- Views: 450
Re: empirical vs molecular
Additionally, using the empirical formula and knowing the molar mass allows you to find the molecular formula by dividing the molar mass by the mass of the empirical compound to find the actual number of atoms in the molecular formula compared to the ratio.
- Thu Apr 19, 2018 11:28 am
- Forum: Einstein Equation
- Topic: Homework 1.25b
- Replies: 1
- Views: 170
Homework 1.25b
1.25 Sodium vapor lamps, used for public lighting, emit yellow light of wavelength 589 nm. How much energy is emitted by (b) 5.00 mg of sodium atoms emitting light at this wavelength; Hi, I was slightly confused on following the steps for part b. I was wondering if someone could explain them more th...
- Thu Apr 19, 2018 11:16 am
- Forum: Balancing Chemical Reactions
- Topic: Balancing Equation
- Replies: 7
- Views: 742
Re: Balancing Equation
Personally, I like to look for the element that is present the least on both sides as a starting point. From there I try to start with the elements that have smaller quantities present on both sides of the reaction. In addition, like the example Dr. Lavelle used in class I will utilize fractions and...
- Sun Apr 15, 2018 8:58 pm
- Forum: Photoelectric Effect
- Topic: Threshold Energy [ENDORSED]
- Replies: 12
- Views: 732
Re: Threshold Energy [ENDORSED]
To add on, the photoelectric effect is the idea that there is an ejection of electrons from a metal when its surface is exposed to ultraviolet radiation. Furthermore, no electrons are ejected unless the radiation has a frequency above a certain threshold that is characteristic of a metal.
- Sun Apr 15, 2018 8:52 pm
- Forum: Photoelectric Effect
- Topic: Example 1.5 in the textbook [ENDORSED]
- Replies: 2
- Views: 232
Re: Example 1.5 in the textbook [ENDORSED]
The question asks you to arrange the following electromagnetic radiation in order of increasing energy. After you find the frequency, you use that value and multiply it by plancks constant not divide to find the value of energy (E=hv). You then rank the radiations for increasing energy. You can also...
- Sun Apr 15, 2018 8:47 pm
- Forum: *Black Body Radiation
- Topic: What is Significant about Black Body Radiation? [ENDORSED]
- Replies: 4
- Views: 751
Re: What is Significant about Black Body Radiation? [ENDORSED]
Additionally, blackbody radiation is a theoretical concept in quantum mechanics in which a material or substance completely absorbs all frequencies of light and therefore reflects no radiation and appears black. An example would be a star. Most of the light directed at the star is absorbed, capable ...
- Sun Apr 15, 2018 8:37 pm
- Forum: Properties of Light
- Topic: HW ch1 question 5
- Replies: 3
- Views: 187
Re: HW ch1 question 5
The question from the textbook says: Arrange the following types of photons of electromagnetic radiation in order of increasing energy: -rays, visible light, ultraviolet radiation, microwaves, x-rays. Like the student above, said you know that the speed of light, c, equals lambda*v(the frequency), t...
- Sun Apr 15, 2018 8:26 pm
- Forum: Properties of Light
- Topic: HW 1.7 (using nm vs pm)
- Replies: 8
- Views: 431
Re: HW 1.7 (using nm vs pm)
I agree with what everyone else said. In addition, I think the answer was trying to show the value without scientific notation and in terms that would help you understand the scope of the problem and compare that to the answer and its units.
- Sun Apr 15, 2018 8:22 pm
- Forum: Properties of Light
- Topic: HW 1.5 [ENDORSED]
- Replies: 2
- Views: 158
Re: HW 1.5 [ENDORSED]
The colors of photons of the electromagnetic radiation refer to visible light and the different colors that you see. Visible light ranges from 700nm (red light) to 400 nm (violet light) which has a spectrum of colors within that range. The wavelengths represent the different regions of the spectrum ...
- Sun Apr 15, 2018 7:46 pm
- Forum: Ionic & Covalent Bonds
- Topic: C2+ C2-
- Replies: 4
- Views: 1578
Re: C2+ C2-
In addition, if you focus on the valence electrons, there would be 8 electrons for C2- while there would only be 4 electrons for C2+. Therefore, the 8 electrons would fill up both outer orbitals, the s and p orbitals, while for C2- it would only fill up the 1s orbital and have 2 electrons in the 2s ...