Search found 35 matches

by Rohan Kubba Dis 4B
Fri Nov 15, 2019 9:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs Nonpolar Example
Replies: 3
Views: 23

Re:olar vs Nonpolar Example

Basically, a good example to look up is 2E30. (Yes I know it is an even question, but it is a good example). If you look at it there are three forms of essentially the same element. In the second and third versions, these are the trans and cis versions of the molecules respectively. Essentially in t...
by Rohan Kubba Dis 4B
Fri Nov 15, 2019 9:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: seesaw
Replies: 9
Views: 37

Re: seesaw

Essentially this is when there are 4 bonds to a central atom and a lone pair. (AX4E). This can also be called sawhorse though.
by Rohan Kubba Dis 4B
Fri Nov 15, 2019 9:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 22

Re: Bond Angles

If you are referring to substances with the same electronic configuration, this is because the lone pairs of a substance affect the molecular geometry of substance more than atoms. In other words, if you look at rule 4 in the book, it explains that lone pairs repel the other atoms more than atoms an...
by Rohan Kubba Dis 4B
Fri Nov 15, 2019 9:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: London dispersion forces and vander waals
Replies: 5
Views: 30

Re: London dispersion forces and vander waals

An example of a van der waal force would be that of a sample of Helium. Essentially, it has a full valence shell and it would have a momentary dipole (one side of atom is positive and the other side is negative), therefore another helium atom could interact with its positive portion to the negative ...
by Rohan Kubba Dis 4B
Fri Nov 15, 2019 8:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Notation
Replies: 5
Views: 21

Re: VSEPR Notation

A refers to the central atom, X refers to the number of bonds and E represents lone pairs. However, just remember when you have a radical, you treat that lone electron like a loan pair. So, essentially, E usually represents lone pairs of electrons, however it is important to note that radicals are t...
by Rohan Kubba Dis 4B
Sun Nov 10, 2019 2:03 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Equation?
Replies: 12
Views: 42

Re: Formal Charge Equation?

Also, my TA I taught us a really easy way: Valence electrons of element-(number of bonds(lines) + the number of lone electrons(not pairs)). This seemed to work for me and it was fast too. Another trick I learned was that when finding the formal charge for oxygen, if it was double bonded and had two ...
by Rohan Kubba Dis 4B
Sun Nov 10, 2019 1:53 pm
Forum: Electronegativity
Topic: Ionization energy of O vs N
Replies: 6
Views: 27

Re: Ionization energy of O vs N

This is the main deviation of the periodic trend of ionization energy increasing to the right and up (fluorine). In this case, nitrogen has a a higher ionization energy than oxygen. The reason is because if you look at the 2p shells of each element, you will see that oxygen has 4 total electrons in ...
by Rohan Kubba Dis 4B
Sun Nov 10, 2019 1:47 pm
Forum: Octet Exceptions
Topic: octet exceptions
Replies: 11
Views: 71

Re: octet exceptions

There are many octet exceptions. First, H only needs one electron to complete its shell, and this extends to He and a couple of other elements. Next, we have expanded octets which can be any element in the third period which includes P, S, and Cl. Moreover, then we have radicals and biradicals. Alth...
by Rohan Kubba Dis 4B
Sun Nov 10, 2019 1:41 pm
Forum: Dipole Moments
Topic: Dipoles Cancelling Out
Replies: 4
Views: 22

Dipoles Cancelling Out

When would dipoles cancel out. For instance, CH4 (methane) has two different elements yet all the dipoles “cancel out”; when would I know when other elements have dipoles the cancel out? Would I just have to draw them and evaluate?
by Rohan Kubba Dis 4B
Sun Nov 10, 2019 1:38 pm
Forum: Dipole Moments
Topic: Dipoles between the same elements
Replies: 3
Views: 10

Dipoles between the same elements

Do elements that are diatomic like O2 or Br2 have dipoles or is it only between molecules?
by Rohan Kubba Dis 4B
Sat Nov 02, 2019 11:12 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Cu and Cr
Replies: 11
Views: 39

Cu and Cr

Obviously Copper and Chromium have special electron configurations to maintain stability (3d10 4s1 and 3d5 4s1), however, does this trend continue to the corresponding elements in each group (Molybdenum for Chromium and Silver for Copper)?
by Rohan Kubba Dis 4B
Sat Nov 02, 2019 11:08 am
Forum: Octet Exceptions
Topic: Expanded Octet
Replies: 3
Views: 14

Expanded Octet

I understand that some elements like S and P can have more than 8 valence electrons, however, is their a way to determine what other elements have the same condition? How would you derive the amount of valence electrons for an element like these? Do we just memorize these exceptions in the table and...
by Rohan Kubba Dis 4B
Sat Nov 02, 2019 11:02 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Understanding Ionic Radius
Replies: 3
Views: 17

Understanding Ionic Radius

In the review session, the UAs mentioned three ions that were isoelectronic, meaning they were equal in valence electrons, however, in this case they explained that ionic radius still increases as you move down a group and increases as you go down a period. I’m just confused as to why this is the ca...
by Rohan Kubba Dis 4B
Sat Nov 02, 2019 10:56 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Ionization Energy
Replies: 3
Views: 17

Ionization Energy

I know at the review session, the UAs explained that oxygen has a lower ionization energy than nitrogen because nitrogen has a symmetrical arrangement while oxygen does not. Are there any other cases that differ from the general trend of ionization energy increasing to the right and up the table lik...
by Rohan Kubba Dis 4B
Sat Nov 02, 2019 10:53 am
Forum: Octet Exceptions
Topic: Odd number of valence electrons
Replies: 2
Views: 11

Odd number of valence electrons

I understand that sometimes we are going to be given a molecule and we may not have enough electrons to fill up all the shells. In these cases, with an odd number of electrons, where do we give that extra electron to? In other words, which element gets the extra electron? Does it have to do with ele...
by Rohan Kubba Dis 4B
Sun Oct 27, 2019 5:22 pm
Forum: Lewis Structures
Topic: expanded-octet
Replies: 4
Views: 18

Re: expanded-octet

Is there a general rule for the d-block elements for the expanded octet, or is it completely variable from element to element? Also, how are we able to derive the expanded octet numbers from these elements?
by Rohan Kubba Dis 4B
Sun Oct 27, 2019 5:12 pm
Forum: Lewis Structures
Topic: Reasoning for the octet
Replies: 3
Views: 22

Re: Reasoning for the octet

Essentially, you are right, each atom wants to be fully stable, and while there are other factors, such as electrostatic attraction, that ultimately impact bonding, the idea is that each atom wants to fill its outer electron shells to achieve the highest energy level it can. Of course, Hydrogen just...
by Rohan Kubba Dis 4B
Sun Oct 27, 2019 5:03 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability vs. Polarizing Power
Replies: 3
Views: 173

Re: Polarizability vs. Polarizing Power

Also, higher polarizable atoms are typically atoms with electrons that are far away from the nucleus, (many shells), and because the electrons are further away, the electron cloud is large and highly polarizable as denoted by the textbook. Also, cations are generally not highly polarizable because t...
by Rohan Kubba Dis 4B
Sun Oct 27, 2019 4:55 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic v Covalent Bond
Replies: 3
Views: 42

Ionic v Covalent Bond

I understand that there are not truly any definite values that dictate whether a bond is covalent or ionic. However, in the book it says that a good rule of thumb is that an electronegativity difference of two means that the bond has so much ionic character, it is best regarded as ionic. Are there a...
by Rohan Kubba Dis 4B
Sun Oct 27, 2019 4:50 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 6
Views: 243

Re: Electronegativity

A good rule of thumb when dealing with electronegativity is that as you are going across a period, generally, that has more impact than variance within a group. In other words, that electronegativity is usually closer across a period. With that in mind, even though Chlorine is in the same group as f...
by Rohan Kubba Dis 4B
Sat Oct 19, 2019 7:13 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: P Orbital specifics
Replies: 4
Views: 29

P Orbital specifics

I understand that the P orbital has an x, y, and z portion to it depending on the element; however, is the ordering of the orbitals arbitrary? In other words, are we defining the axes first and then deciding that they are x, y or z? Because from different perspectives, the x-axis can be the y-axis a...
by Rohan Kubba Dis 4B
Sat Oct 19, 2019 7:12 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: More Energy levels
Replies: 1
Views: 18

More Energy levels

Why is it that when we are dealing with energy levels, as the energy levels increase, they get closer together? Does this also affect our calculations with the Bohr frequency condition or the E=-hR/n^2 formula in any way?
by Rohan Kubba Dis 4B
Sat Oct 19, 2019 7:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Applications of Hund’s Rule and Pauli Exclusion Principle
Replies: 2
Views: 18

Applications of Hund’s Rule and Pauli Exclusion Principle

Can someone please describe Hund’s Rule and the Pauli Exclusion Principle, and its direct correlation to how it helps us write e- configurations? I am confused on when each one is applicable and not.
by Rohan Kubba Dis 4B
Sat Oct 19, 2019 7:10 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions
Replies: 2
Views: 36

Exceptions

Can someone please explain the exceptions to the multi-electron atoms? If someone could use some examples and explanations to describe these special cases, it would be much appreciated.
by Rohan Kubba Dis 4B
Sat Oct 19, 2019 7:09 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: More Orbital Understanding
Replies: 3
Views: 35

More Orbital Understanding

I understand that the orbital is a probability field of the highest likelihood of the atoms position, however, is the probability uniform throughout the orbital or is it more likely to be near the nucleus and why?
by Rohan Kubba Dis 4B
Sat Oct 12, 2019 1:47 pm
Forum: Properties of Electrons
Topic: Properties of electron being Particle v Wave
Replies: 3
Views: 28

Properties of electron being Particle v Wave

I understand that electrons have a duality of having particle-like properties as well as wave-like properties, however, what are the exact examples or properties or that make each side valid? (Atomic Spectra, Photoelectric effect, etc.)
by Rohan Kubba Dis 4B
Sat Oct 12, 2019 1:31 pm
Forum: Properties of Light
Topic: Speed of Light
Replies: 41
Views: 796

Re: Speed of Light

Unless we are not in a vacuum, the speed of light will stay constant at 3.0 x 10^8 m/s.
by Rohan Kubba Dis 4B
Sat Oct 12, 2019 1:20 pm
Forum: Properties of Light
Topic: What exactly is diffraction?
Replies: 3
Views: 22

Re: What exactly is diffraction?

Diffraction, in our context, refers to the patterns of high and blow intensities generated by an object in the path of a ray of light. Basically, it is referring to the idea of constructive and destructive interference that shows the wave-like properties of electromagnetic rays.
by Rohan Kubba Dis 4B
Sat Oct 12, 2019 1:14 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Intensity of Light
Replies: 7
Views: 42

Re: Photoelectric Effect Intensity of Light

Another important aspect to remember is that each photon interacts with only one electron, and furthermore, if you increase the intensity of the light and if you have enough energy per photon, then more electrons would be emitted.
by Rohan Kubba Dis 4B
Sat Oct 12, 2019 1:06 pm
Forum: Properties of Electrons
Topic: Constructive and Destructive Interference
Replies: 4
Views: 49

Re: Constructive and Destructive Interference

Another way to think of constructive v destructive waves is that when two waves are in phase, meaning they are both peaks or both troughs at the same moment, you add them. These are constructive waves. Moreover, when two waves are out of phase, meaning one is a trough and the other is a peak at the ...
by Rohan Kubba Dis 4B
Thu Oct 03, 2019 2:31 pm
Forum: SI Units, Unit Conversions
Topic: Sig Fig Mistakes
Replies: 17
Views: 127

Re: Sig Fig Mistakes

The general idea for sig figs is that you are trying to be precise because your calculation is only as accurate as your least accurate measurement. For example for the hypothetical problem find moles of F- in 25.2kg of UF6, it is important to round your answer to three sig figs at the end. The reaso...
by Rohan Kubba Dis 4B
Thu Oct 03, 2019 2:25 pm
Forum: Balancing Chemical Reactions
Topic: Naming ionic/ molecular compounds
Replies: 7
Views: 82

Re: Naming ionic/ molecular compound

In the periodic table, there are elements (mainly from groups 3-12) that have variable amounts of electrons present. In this case the difference between Iron (II) (ferrous) and Iron (III) (ferric) is that in iron (II), the iron atom has lost two electrons to form Iron (II) and in iron (III) the iron...
by Rohan Kubba Dis 4B
Thu Oct 03, 2019 2:19 pm
Forum: Empirical & Molecular Formulas
Topic: Fundamentals F.25
Replies: 3
Views: 30

Re: Fundamentals F.25

Basically, on that question you count the figures of each type of element. You then have your molecular formula, which would be C4H6Cl2. That would be your molecular formula. Then, you would divide by the greatest common factor. In essence, divide by 2 and you would get C2H3C6, which would be your e...
by Rohan Kubba Dis 4B
Thu Oct 03, 2019 12:13 am
Forum: Molarity, Solutions, Dilutions
Topic: M1V1=M2V2 [ENDORSED]
Replies: 3
Views: 41

M1V1=M2V2 [ENDORSED]

I understand that the molarity equation is M1V1=M2V2, however the molarity equation is = to M=n/V. So, basically, I am asking about the idea that shouldn’t the volume cancel out in the M1V1=M2V2. I know my thinking is wrong but I just need a plausible explanation for it.
by Rohan Kubba Dis 4B
Thu Oct 03, 2019 12:05 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Moles
Replies: 5
Views: 36

Re: Moles

A key component to remember how to solve for the moles of F- ions in 25.2 kg of UF6 is to understand the idea of the molar ratio. That means that for ever one atom of U there are 6 atoms of F, so your conversion factor is 1 to 6. So, that means you could solve this by first solving for the moles for...

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