Search found 30 matches

by Luis Avalos 1D
Tue Jun 05, 2018 6:10 pm
Forum: Lewis Acids & Bases
Topic: 12.13.A Significance of lone pairs in determining Lewis acid/base?
Replies: 3
Views: 73

Re: 12.13.A Significance of lone pairs in determining Lewis acid/base?

Lewis acids are lone pair acceptors while bases are donors. This means that if a molecule has a lone pair on the central atom, it will be a lewis base, just like ammonia.
by Luis Avalos 1D
Tue Jun 05, 2018 6:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Planar vs Trigonal Pyramidal
Replies: 5
Views: 270

Re: Trigonal Planar vs Trigonal Pyramidal

As people have stated, it has everything to do with lone pairs on the central atom
by Luis Avalos 1D
Tue Jun 05, 2018 6:03 pm
Forum: Bronsted Acids & Bases
Topic: How to identify a Bronsted acid or base
Replies: 11
Views: 373

Re: How to identify a Bronsted acid or base

Bronsted acids donate protons (H+) while bronsted bases accept protons.
by Luis Avalos 1D
Tue May 29, 2018 7:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework 4.7
Replies: 3
Views: 144

Re: Homework 4.7

Since it's trigonal pyramidal, I think you're right that the angles are all the same.
by Luis Avalos 1D
Tue May 29, 2018 7:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Form vs. Shape
Replies: 2
Views: 44

Re: Form vs. Shape

I believe form refers to all the electron regions around the central atom (including lone pairs), while shape does not account for the lone pair regions. In the case of water, there are 4 electron regions which would create a tetrahedral form, but since we don't count lone pairs in shape it's just b...
by Luis Avalos 1D
Mon May 28, 2018 2:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSPER MODEL
Replies: 3
Views: 71

Re: VSPER MODEL

I'm pretty sure Lavelle mentioned resonance structures don't affect VSEPR models, but lone pairs do.
by Luis Avalos 1D
Sun May 20, 2018 11:29 pm
Forum: Lewis Structures
Topic: central atom
Replies: 7
Views: 80

Re: central atom

It's generally the least electronegative element that's in the middle.
by Luis Avalos 1D
Sun May 20, 2018 11:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Stable Lewis structures
Replies: 4
Views: 95

Re: Stable Lewis structures

You basically want the structure with the least amount of charge which is found by calculating each element's formal charge. Ideally, there should be a formal charge of 0 for each element present.
by Luis Avalos 1D
Sun May 20, 2018 11:25 pm
Forum: Ionic & Covalent Bonds
Topic: Test 3
Replies: 2
Views: 90

Re: Test 3

The website says test 3 covers chapter 3 material so I think it'd be useful to review what we've gone over in lecture.
by Luis Avalos 1D
Tue May 15, 2018 9:22 am
Forum: Trends in The Periodic Table
Topic: 2.6B
Replies: 2
Views: 123

Re: 2.6B

Beryllium has 4 electrons which means that if we remove 3, we will be in the 1s shell (the core). On the other hand, when we remove 3 electrons from Boron (has 5 electrons), we only remove the valence electrons (the 2s and 2p). As stated, it is way harder to remove these innermost electrons than it ...
by Luis Avalos 1D
Tue May 15, 2018 9:18 am
Forum: Lewis Structures
Topic: Identifying elements in Lewis structures [ENDORSED]
Replies: 2
Views: 94

Re: Identifying elements in Lewis structures [ENDORSED]

It specifically says "period 3 element" which is Na through Ar, and nitrogen is a period 2 element. On top of this, the central atom does not strictly follow the octet rule which is also an indication that it would not be nitrogen.
by Luis Avalos 1D
Tue May 15, 2018 9:14 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge terms
Replies: 2
Views: 81

Re: Formal Charge terms

I like to do the following formula to calculate it:

formal charge = valence electrons of the atom - (lone pairs + .5* bonded electrons).
by Luis Avalos 1D
Sat May 05, 2018 8:21 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations Exceptions
Replies: 3
Views: 61

Re: Electron Configurations Exceptions

I think molybdenum is part of this list as well, and you just need to remember that those elements will take an e- from the s shell to fill the d shells (singly for Mo and Cr, and doubly for Cu and Ag).
by Luis Avalos 1D
Sat May 05, 2018 7:02 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions for electron configuration
Replies: 3
Views: 94

Re: Exceptions for electron configuration

In period 4, Chromium and Copper fill their shells differently than you'd expect. Instead of Chromium having the electron configuration [Ar] 3d 4 4s 2 , it's actually more stable with the following configuration [Ar] 3d 5 4s 1 . Likewise, Copper is expected to be [Ar] 3d 9 4s 2 but it fills the d sh...
by Luis Avalos 1D
Sat May 05, 2018 6:55 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: D and S oribitals
Replies: 3
Views: 80

Re: D and S oribitals

If you're asking about writing them out, it's a personal preference I believe. For example, some people would write scandium as [Ar] 4s2 3d1 but others write it as [Ar] 3d1 4s2
by Luis Avalos 1D
Tue May 01, 2018 7:02 pm
Forum: Quantum Numbers and The H-Atom
Topic: question on a problem
Replies: 1
Views: 68

Re: question on a problem

Yup! Since only one electron can have that positive spin number, the answer is 1.
by Luis Avalos 1D
Mon Apr 30, 2018 7:51 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: cation or anion?
Replies: 4
Views: 145

Re: cation or anion?

If it gains electrons, it will be negatively charged which is an anion. If it loses electrons, it will be positively charged which is a cation.
by Luis Avalos 1D
Mon Apr 30, 2018 7:45 pm
Forum: *Shrodinger Equation
Topic: How are orbitals corresponding to m sub l numbers
Replies: 2
Views: 130

Re: How are orbitals corresponding to m sub l numbers

If you're referring to m, it corresponds to the magnetic quantum number which tells us the number of orbitals and their orientation, if i'm not mistaken.
by Luis Avalos 1D
Sat Apr 28, 2018 11:53 pm
Forum: Properties of Electrons
Topic: Hydrogen Levels and Energy [ENDORSED]
Replies: 3
Views: 151

Re: Hydrogen Levels and Energy [ENDORSED]

As others have said, higher values of n mean higher energies. If you go from n=1 to n=5, you need more energy to do so than if you went from n=1 to n=2. This also means that more energy is released when the electron returns to the ground state from a higher energy level.
by Luis Avalos 1D
Sat Apr 28, 2018 11:39 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Coefficients in electron configurations [ENDORSED]
Replies: 4
Views: 127

Re: Coefficients in electron configurations [ENDORSED]

As stated, the coefficient represents the corresponding period of the specific element.
by Luis Avalos 1D
Sat Apr 28, 2018 11:32 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Hund's Rule [ENDORSED]
Replies: 6
Views: 178

Re: Hund's Rule [ENDORSED]

Hund's rule is just stating that electrons cannot have paired spins until the other orbitals are all filled first.
by Luis Avalos 1D
Wed Apr 25, 2018 7:30 am
Forum: Photoelectric Effect
Topic: Frequency on Photoelectric Effect
Replies: 5
Views: 162

Re: Frequency on Photoelectric Effect

The number of electrons ejected has to do with the intensity. The photoelectric effect only takes one electron into account without the intensity in mind, I believe.
by Luis Avalos 1D
Wed Apr 25, 2018 7:28 am
Forum: Einstein Equation
Topic: Energy Absorbed in a Mole? - HW Problem #55
Replies: 1
Views: 124

Re: Energy Absorbed in a Mole? - HW Problem #55

Since you found the energy per photon, to find the energy of a mol of photons all you'd have to do is multiply by avogadro's number which is 6.022 x10^23
by Luis Avalos 1D
Wed Apr 25, 2018 7:26 am
Forum: Photoelectric Effect
Topic: calculating the number of photons
Replies: 2
Views: 78

Re: calculating the number of photons

Divide the total number of Joules emitted by the amount of energy per photon!
by Luis Avalos 1D
Mon Apr 16, 2018 11:11 pm
Forum: Limiting Reactant Calculations
Topic: moles + limiting reactant
Replies: 2
Views: 163

Re: moles + limiting reactant

You can always plug the values of the reactants, one at a time, into the equation and whichever yields less product will be the limiting reactant.
by Luis Avalos 1D
Mon Apr 16, 2018 11:09 pm
Forum: Properties of Light
Topic: HW 1.15
Replies: 4
Views: 139

Re: HW 1.15

Because the wavelength 102.6 nm corresponds to the lyman series, we know that the energy level, n1, will be at the ground state (n=1).
by Luis Avalos 1D
Mon Apr 16, 2018 11:02 pm
Forum: Properties of Light
Topic: 1.13 (b)
Replies: 6
Views: 161

Re: 1.13 (b)

As others have said, your answer should be written in terms of nanometers. I got .486 x 10^-6 which translates to 486 x 10^-9 (486 nanometers). This wavelength corresponds to the balmer series, but more specifically, blue visible light.
by Luis Avalos 1D
Mon Apr 16, 2018 10:56 pm
Forum: Properties of Light
Topic: The speed of light
Replies: 4
Views: 125

Re: The speed of light

In a vacuum, yes. The only thing that's different is their frequencies & wavelengths I believe.
by Luis Avalos 1D
Wed Apr 11, 2018 10:43 am
Forum: Limiting Reactant Calculations
Topic: Mass of Products VS. Mass of Reactants- Class Assessment
Replies: 5
Views: 161

Re: Mass of Products VS. Mass of Reactants- Class Assessment

Like everyone else is saying, chemistry strictly follows the law of conservation of mass. What we would ideally observe is the same masses, but sometimes mass is lost when we transfer the products elsewhere.
by Luis Avalos 1D
Wed Apr 11, 2018 10:37 am
Forum: Molarity, Solutions, Dilutions
Topic: Ionic Concentrations
Replies: 1
Views: 70

Ionic Concentrations

How exactly do you find ionic concentrations when salts are dissolved in water?

Go to advanced search