Search found 33 matches

by Tahlia Mullins
Tue Nov 19, 2019 9:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Can linear molecular shapes have lone pair?
Replies: 2
Views: 8

Re: Can linear molecular shapes have lone pair?

I found it useful to create a chart of shape with the steric number being the "y-axis" and the number of lone pairs being the "x-axis", and this would show that for AX2E3 and AX2E, the shape is linear and the angle is 180.
by Tahlia Mullins
Tue Nov 19, 2019 9:34 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: polarizability of anions
Replies: 3
Views: 15

Re: polarizability of anions

Larger molecules are typically more polarizable than smaller ones, meaning that polarizability decreases from left to right and increases as you go down the periodic table.
by Tahlia Mullins
Tue Nov 19, 2019 9:28 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Dipole-Dipole
Replies: 4
Views: 27

Re: Dipole-Dipole

If the dipole moments cancel each other out, the molecule is no longer polar, it is non-polar, and there is no dipole moment. I like to consider this in terms of electronegativity and the relative charges on molecules, instead of just memorizing facts.
by Tahlia Mullins
Tue Nov 19, 2019 9:25 pm
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 bonding
Replies: 3
Views: 11

Re: Hydrogen bonding

N, O, and F each have very high electronegativity, with F being the highest, which allows for the dipole moment to be created when they bond with hydrogen, which is not very electronegativity.
by Tahlia Mullins
Sun Nov 03, 2019 7:52 pm
Forum: Formal Charge and Oxidation Numbers
Topic: When to calculate formal charge
Replies: 7
Views: 35

Re: When to calculate formal charge

I do not think it is absolutely necessary every time, but it is a good way to check that the lewis structure is the best possible for the molecule.
by Tahlia Mullins
Sun Nov 03, 2019 7:49 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Stability
Replies: 3
Views: 25

Re: Formal Charge Stability

Since atoms are most stable when they share their valence electrons equally in bonding, and valence electrons is the first term in the formal charge formula, if the formal charge is 0, the previously stated will be fulfilled, making it more stable.
by Tahlia Mullins
Sun Nov 03, 2019 7:43 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge purpose
Replies: 40
Views: 1460

Re: Formal charge purpose

Especially when dealing with resonance, finding the formal charge of each lewis structure is essential to determining the most stable structure, with a formal charge of 0 or as close to 0 as possible.
by Tahlia Mullins
Sun Nov 03, 2019 7:39 pm
Forum: Bond Lengths & Energies
Topic: Strength of Bonds
Replies: 16
Views: 37

Re: Strength of Bonds

Shorter bonds are stronger. Double and triple bonds are shorter than single bonds, so these types of bonds are stronger.
by Tahlia Mullins
Sun Nov 03, 2019 7:34 pm
Forum: Bond Lengths & Energies
Topic: Bond Strength
Replies: 6
Views: 17

Re: Bond Strength

When the bond length is shorter, as with double and triple bonds, which involve more electrons being shared between atoms, the atoms are closer together, and there is a stronger energy due to the atomic radii in relation to the distance between the nuclei of each atom being shorter, making the pull ...
by Tahlia Mullins
Sat Oct 26, 2019 11:52 pm
Forum: Ionic & Covalent Bonds
Topic: How are lewis structures filled?
Replies: 6
Views: 39

Re: How are lewis structures filled?

I agree that it is best to think of the drawing of lewis dot structures as similar to electron configurations, following Hund's rule in the distribution of dots/arrows.
by Tahlia Mullins
Sat Oct 26, 2019 11:39 pm
Forum: Ionic & Covalent Bonds
Topic: "Delocalized" Electrons
Replies: 5
Views: 42

Re: "Delocalized" Electrons

I agree with the responses already given, but I would also like to add that I find it easier to think of delocalized as a synonym for mobile, meaning the electrons can move around, hence resonance.
by Tahlia Mullins
Sat Oct 26, 2019 11:22 pm
Forum: Ionic & Covalent Bonds
Topic: Resonance
Replies: 12
Views: 76

Re: Resonance

Compounds with resonance are more stable because their electrons are delocalized, or more mobile, which leads to a lower overall energy since the electrons occupy a greater volume.
by Tahlia Mullins
Sat Oct 26, 2019 11:19 pm
Forum: Ionic & Covalent Bonds
Topic: lewis structures for diff bonds
Replies: 5
Views: 63

Re: lewis structures for diff bonds

Yes, and I agree with what has already been said. Just wanted to add that I find drawing the lewis dot structures helps tremendously with understanding the exact exchange/sharing of electrons that is occurring with each bond!
by Tahlia Mullins
Sat Oct 26, 2019 11:15 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic and Covalent Bonds
Replies: 5
Views: 21

Re: Ionic and Covalent Bonds

Drawing Lewis dot structures definitely helps in depicting both of these types of bonds. In an ionic bond, between a metal and a nonmetal, one atom gives up an electron to make both atoms more stable, and this is shown with anion and cation depictions(+/-). In a covalent bond, between nonmetals, two...
by Tahlia Mullins
Sun Oct 20, 2019 8:49 pm
Forum: Trends in The Periodic Table
Topic: electronegativity
Replies: 10
Views: 331

Re: electronegativity

It can also be added that electronegativity has an inverse relationship with atomic radius, therefore has an opposite periodic trend. This is because a larger atomic radius usually means more shielding experienced by the nucleus, giving it less affinity for attracting electrons from other atoms.
by Tahlia Mullins
Sun Oct 20, 2019 8:41 pm
Forum: Trends in The Periodic Table
Topic: ionization energy
Replies: 11
Views: 271

Re: ionization energy

A good way to remember what this is would be to relate its trends to the trends in atomic radius since the larger the atomic radius, the greater the ionization energy, so their trends line up since they are in direct relationship with one another.
by Tahlia Mullins
Sun Oct 20, 2019 8:38 pm
Forum: Trends in The Periodic Table
Topic: Study Buddies?
Replies: 8
Views: 59

Re: Study Buddies?

I'm in! My email is Tahlia.rose46@gmail.com.
by Tahlia Mullins
Sun Oct 20, 2019 8:37 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Pauli Exclusion Principle
Replies: 9
Views: 38

Re: Pauli Exclusion Principle

The Pauli Exclusion Principle basically states that each orbital can only have two electrons, and since they are in the same orbital, these electrons must have opposite spins, which is shown by the arrows pointing in the opposite direction.
by Tahlia Mullins
Sun Oct 20, 2019 8:28 pm
Forum: Trends in The Periodic Table
Topic: Atomic radii
Replies: 9
Views: 38

Re: Atomic radii

I think it is important to stress theft that the electrons are being added to the same shell when moving from left to right, therefore the atomic radius does not increase too drastically. At the same time, there are more protons in the nucleus, pulling the electrons in closer, decreasing the atomic ...
by Tahlia Mullins
Sun Oct 20, 2019 8:19 pm
Forum: Quantum Numbers and The H-Atom
Topic: Orbitals
Replies: 4
Views: 23

Re: Orbitals

This is also consistent in observing the atomic radius. The more shielding of electrons/the more orbitals, the larger the atomic radius.
by Tahlia Mullins
Sun Oct 20, 2019 8:15 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Hund's rule and Pauli Exclusion Principle
Replies: 14
Views: 72

Re: Hund's rule and Pauli Exclusion Principle

Both Hund's Rule and Pauli Exclusion Principle provide the guidelines of the ground state electron configuration for a given atom. Singularly, Hund's Rule provides that each orbital must include one arrow before doubling up. The Pauli Exclusion Principle states that two electrons in the same orbital...
by Tahlia Mullins
Sun Oct 13, 2019 7:54 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Shielding [ENDORSED]
Replies: 15
Views: 713

Re: Shielding [ENDORSED]

Since the 2s orbital is closest to the nucleus, the 2p orbital experiences shielding from the nucleus, increasing the diameter of the atom.
by Tahlia Mullins
Sun Oct 13, 2019 7:51 pm
Forum: Photoelectric Effect
Topic: Electrons ejected based on wavelength
Replies: 3
Views: 25

Re: Electrons ejected based on wavelength

A longer wavelength has a lower frequency, since they have an inverse relationship, and a higher frequency is more effective in reaching the required threshold energy to emit an electron from a given metal surface, which would mean the wavelength is shorter.
by Tahlia Mullins
Sun Oct 13, 2019 7:36 pm
Forum: Photoelectric Effect
Topic: Energy of Photon Clarification
Replies: 4
Views: 51

Re: Energy of Photon Clarification

A good way for me to remember it is that the energy of the photon has to be equal to the or greater than the energy required, calculated by the work function, to emit the electron.
by Tahlia Mullins
Sun Oct 13, 2019 7:32 pm
Forum: Photoelectric Effect
Topic: Avogadro's number
Replies: 7
Views: 59

Re: Avogadro's number

Just a note, Avogadro’s number is actually 6.022*10^23 while planck’s constant is 6.626*10^-34, not to be mixed up! However, these are provided on tests since they are constants.
by Tahlia Mullins
Sun Oct 13, 2019 7:13 pm
Forum: Einstein Equation
Topic: Planck's constant
Replies: 9
Views: 102

Re: Planck's constant

Planck’s constant is a vital component of the e=hv equation because it relates the amount of energy emitted to the speed, is with units J.s
by Tahlia Mullins
Sun Oct 13, 2019 7:02 pm
Forum: Einstein Equation
Topic: E=hv
Replies: 8
Views: 58

Re: E=hv

h is planck’s constant, which is 6.626*10^-34, and I like to remind myself that it is an extremely small number when I am making calculations.
by Tahlia Mullins
Sun Oct 13, 2019 6:54 pm
Forum: Limiting Reactant Calculations
Topic: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]
Replies: 66
Views: 950

Re: Showing Work for Limiting Reactant Calculations on Tests [ENDORSED]

When showing work, I always include units from beginning to end, which makes it easier for the grader to follow as well as serves as a way to check if I got the right answer based on getting down to the right units.
by Tahlia Mullins
Thu Oct 03, 2019 9:06 pm
Forum: Balancing Chemical Reactions
Topic: Understanding how to get whole #s [ENDORSED]
Replies: 18
Views: 131

Re: Understanding how to get whole #s [ENDORSED]

The only time I usually round when calculating moles is when I am writing an empirical or molecular formula, because in a formula, there should not be any decimals/fractions. Although, when I am converting from grams to mols, I do round, at least to the correct number of significant figures.
by Tahlia Mullins
Thu Oct 03, 2019 9:01 pm
Forum: Molarity, Solutions, Dilutions
Topic: G. 7
Replies: 2
Views: 28

Re: G. 7

The above response is perfect, I would also like to add that it would be wise to do the same in order to find the mass of water needed to prepare the solution since it is noted that it is an aqueous solution. To do that, just subtract the mass of KNO3 from 510. Then, go on to explain how to prepare.
by Tahlia Mullins
Thu Oct 03, 2019 8:58 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Actual Yield vs Theoretical Yield
Replies: 6
Views: 40

Re: Actual Yield vs Theoretical Yield

Therefore, since the actual yield is always smaller than the theoretical yield, when performing the percentage yield, actual goes over theoretical. Otherwise, the percentage would be greater than 100.
by Tahlia Mullins
Thu Oct 03, 2019 8:56 pm
Forum: Significant Figures
Topic: Sig figs in intermediate steps??
Replies: 5
Views: 28

Re: Sig figs in intermediate steps??

I completely agree with this reply. I would also like to add that I personally do not write out very integer following the decimal point if there are too many, but I do conserve them in my calculator while performing the calculations. Just a tip in case there is a time constraint.
by Tahlia Mullins
Thu Oct 03, 2019 8:50 pm
Forum: SI Units, Unit Conversions
Topic: mol, g.mol and g.mol-1
Replies: 12
Views: 124

Re: mol, g.mol and g.mol-1

I find it easier to write out g/mol when performing calculations instead of using g.mol-1. Just a tip to make things easier to follow when there may be some heavy stoichiometry!

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