Search found 26 matches
- Tue Jun 05, 2018 2:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Trigonal Planar vs Trigonal Pyramidal
- Replies: 5
- Views: 15955
Re: Trigonal Planar vs Trigonal Pyramidal
trigonal planar has 3 bonding regions and no lone pairs, with sp2 hybridization, while trigonal pyramidal has 3 bonding regions, 1 lone pair and sp3 hybridization. also in 3D trigonal planar would be like a flat triangle while trigonal pyramidal is pyramid-shaped
- Tue Jun 05, 2018 2:52 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Problem 17.29
- Replies: 3
- Views: 359
Re: Problem 17.29
my TA said we don't need to know that, however I think you're more or less correct and also using the charges of the other atoms/ions in the molecule can be used to find the ligand's charge.
- Tue Jun 05, 2018 2:50 pm
- Forum: Lewis Acids & Bases
- Topic: Strength between 2 weak/strong acids/bases
- Replies: 5
- Views: 798
Re: Strength between 2 weak/strong acids/bases
^yes, the more easily an acid/base dissociates the stronger it is. However, I don't think you'd actually know for sure unless you compared the acid/base dissociation constants, which we haven't used this quarter.
- Tue Jun 05, 2018 2:35 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Hybridization
- Replies: 7
- Views: 829
Re: Hybridization
The hybridization correlates with the number of electron pair regions around the central atom, so linear (2) would be sp, trigonal planar (3) is sp2 (add another p), tetrahedral (4) is sp3, then move on to d, etc etc.
- Tue Jun 05, 2018 2:33 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligands
- Replies: 3
- Views: 428
Re: Ligands
a ligand is an ion/molecule that binds to a central metal atom, usually through donation of at least one of the ligand's electron pairs.
- Tue May 29, 2018 4:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond angles and lone pairs
- Replies: 4
- Views: 734
Re: Bond angles and lone pairs
If the bond angle is smaller than usual, then there are more lone pairs. For example, a bent shape with AX2E2 (H2O) has a bond angle of <109.5 while a bent shape with AX2E (O3) has a bond angle of <120.
- Fri May 25, 2018 2:43 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis acid vs. base
- Replies: 5
- Views: 1056
Re: Lewis acid vs. base
Since lewis acids are electron acceptors and bases are electron donors, when you draw the molecule an acid would have space to accept electrons (for example, BF3 can accept a pair to form a full octet) and a base would have extra lone pairs (ex. NH3)
- Mon May 21, 2018 12:10 am
- Forum: Bond Lengths & Energies
- Topic: 3.87
- Replies: 5
- Views: 632
Re: 3.87
The strongest bonds are in CF4, then CCl4, then CBr4. This is because F has the smallest atomic radius, which results in a shorter bond length and a stronger bond.
- Mon May 21, 2018 12:05 am
- Forum: Dipole Moments
- Topic: Difference between Dipole-Dipole and Dipole-Induced dipole?
- Replies: 2
- Views: 423
Re: Difference between Dipole-Dipole and Dipole-Induced dipole?
H-F already has dipoles, so in H-F H-F the negative dipole of F interacts with the positive H on the other molecule in a dipole-dipole interaction. In H-Cl N-N, N-N is neutral (has no dipoles) while H-Cl is positive at H and negative at Cl. The dipoles in H-Cl attract/repel electrons in N-N and caus...
- Mon May 21, 2018 12:00 am
- Forum: Electronegativity
- Topic: Electronegativiry vs electron affinity [ENDORSED]
- Replies: 4
- Views: 959
Re: Electronegativiry vs electron affinity [ENDORSED]
The trends are the same - they both increase upward and to the right. Electronegativity is the ability for a bonded atom to attract bonding electrons to itself while electron affinity is a measurable value (the energy change when an atom gains an electron).
- Sun May 20, 2018 5:11 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarization
- Replies: 2
- Views: 418
Re: Polarization
The anion holds its electrons less tightly than the cation does, due to greater shielding/repulsion caused by the additional electrons - as a result, its cloud is more susceptible to distortion
- Sun May 13, 2018 11:34 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: How do I determine Formal Charge?
- Replies: 2
- Views: 448
Re: How do I determine Formal Charge?
Yes, ideally you would try to draw the molecule in such a way that the formal charge of each atom is 0. However, in cases like an odd number of electrons (ex. NO), incomplete octets (ex. BF3), or expanded valence shells (atoms with 3d and up), the octet rule can be broken and the formal charges can ...
- Sun May 13, 2018 11:08 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bonds
- Replies: 4
- Views: 666
Re: Covalent Bonds
The central atom has to bond with more atoms around it - a central atom with lower ionization energy would more readily share its electrons (since it's not "holding onto" its electrons as tightly). Also, atoms with higher ionization energy usually have more lone pairs, which would cause mo...
- Mon May 07, 2018 3:19 am
- Forum: Trends in The Periodic Table
- Topic: Difference between Periodic trends [ENDORSED]
- Replies: 4
- Views: 638
Re: Difference between Periodic trends [ENDORSED]
Electron affinity is a measure of energy change when an electron is added while electronegativity is how attracted an atom is to electrons. While electron affinity is increasing, electronegativity is decreasing since as an atom is less attractive to electrons, it requires more energy to add an elect...
- Mon May 07, 2018 3:15 am
- Forum: Trends in The Periodic Table
- Topic: 2.67 part c) and d) [ENDORSED]
- Replies: 5
- Views: 657
Re: 2.67 part c) and d) [ENDORSED]
Chlorine and lithium have higher electron affinity than bromine and sodium because as you go up a group, there is less shielding and you're closer to the nucleus, making it easier to add electrons. When an electron is added to a neutral atom, energy is released, and the harder it is to add electrons...
- Mon May 07, 2018 2:52 am
- Forum: Trends in The Periodic Table
- Topic: Across vs Down Trend
- Replies: 2
- Views: 363
Re: Across vs Down Trend
Across a period the radius gets smaller while down a group it gets bigger. Since silver is lower and to the left, it is bigger than zinc in both aspects. Comparing elements like nitrogen and sulfur would be more ambiguous, however it's not likely that questions like that would be asked.
- Mon May 07, 2018 2:45 am
- Forum: Ionic & Covalent Bonds
- Topic: Help on 3.9 (b) [ENDORSED]
- Replies: 2
- Views: 347
Re: Help on 3.9 (b) [ENDORSED]
M2+ means that the atom has lost two electrons. That means without the 2+ charge it would be [Ar]3d^(6)4s^(2), which is Fe, so M is Fe
- Mon Apr 30, 2018 3:35 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Nodal Planes- what are they exactly? [ENDORSED]
- Replies: 6
- Views: 16144
Re: Nodal Planes- what are they exactly? [ENDORSED]
Nodal planes are where you won't find any electrons.
Radial nodal planes are spheres that occur as N increases (between s shells, # angular planes = N-L-1)
Angular nodal planes are flat and occur within orbitals (# angular planes = L)
Radial nodal planes are spheres that occur as N increases (between s shells, # angular planes = N-L-1)
Angular nodal planes are flat and occur within orbitals (# angular planes = L)
- Mon Apr 30, 2018 3:16 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodes
- Replies: 2
- Views: 369
Re: Nodes
Nodes are where there aren't any electrons - radial nodes are spherical, between each electron shell. Angular nodes are flat planes within orbitals. There are n-L-1 radial nodes and L angular nodes For example 3s: has 2 radial nodes and no angular nodes. 2p: has 0 radial nodea and 1 angular node (3 ...
- Mon Apr 30, 2018 3:10 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: HOMEWORK PROBLEM 2.19
- Replies: 3
- Views: 1094
Re: HOMEWORK PROBLEM 2.19
n is the principal quantum number (energy level/shell) while L describes the subshell (s, p, d, f). For part a: Values for L (subshells) ranges from 0 - (n-1), so when n=7, L could be anything from 0-7. Thus, 8 values are possible. You can work backward as well. For parts b and c: ml describes the d...
- Mon Apr 23, 2018 3:14 pm
- Forum: DeBroglie Equation
- Topic: de broglie [ENDORSED]
- Replies: 1
- Views: 285
de broglie [ENDORSED]
In my notes, I have written:
Energy, E= p*v
For a photon: E = p*c and E = hv = hc/λ
How can E equal both p*v and p*c? Or did I write it down wrong
Energy, E= p*v
For a photon: E = p*c and E = hv = hc/λ
How can E equal both p*v and p*c? Or did I write it down wrong
- Mon Apr 23, 2018 3:08 pm
- Forum: Properties of Electrons
- Topic: Example from Lecture #8 [ENDORSED]
- Replies: 2
- Views: 567
Re: Example from Lecture #8 [ENDORSED]
https://s3-us-west-2.amazonaws.com/cour ... 06_00a.jpg
^
The picture linked above explains! the wave on the left is allowed b/c it overlaps with itself perfectly while the one on the right isn't b/c the wave is broken
^
The picture linked above explains! the wave on the left is allowed b/c it overlaps with itself perfectly while the one on the right isn't b/c the wave is broken
- Mon Apr 23, 2018 3:02 pm
- Forum: Einstein Equation
- Topic: finding frequency from Einstein's equation [ENDORSED]
- Replies: 3
- Views: 588
Re: finding frequency from Einstein's equation [ENDORSED]
plug in momentum to λ = h/p to find λ , then plug that into λ =hv to find v
- Sat Apr 14, 2018 5:31 pm
- Forum: Balancing Chemical Reactions
- Topic: Whole numbers
- Replies: 7
- Views: 877
Re: Whole numbers
subscripts are always whole numbers. the coefficients can be fractions while you're balancing to make it easier, but at the end you'd have to multiply everything by a common denominator to get whole numbers
- Sat Apr 14, 2018 5:30 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: dilution
- Replies: 4
- Views: 638
dilution
when you mix one solution of a certain molarity and volume with another solution of a different molarity and volume, how do you find the new molarity? is it just adding everything
- Sat Apr 14, 2018 5:22 pm
- Forum: Limiting Reactant Calculations
- Topic: Two limiting reactants?
- Replies: 10
- Views: 2414
Re: Two limiting reactants?
No, they will either both be completely used up or only one will be in shortage