Search found 139 matches

by Rida Ismail 2E
Tue Nov 05, 2019 1:32 pm
Forum: Lewis Structures
Topic: Central Atom
Replies: 3
Views: 57

Re: Central Atom

I just checked this and C does have the lowest IE.
Ionization energies:
C: 1086.5 KJ/mol
H:1312 KJ/mol
Br:1139.9 KJ/mol

Looking at this the IE of carbon is the lowest out of all of the atoms, therefore it goes in the center.
by Rida Ismail 2E
Tue Nov 05, 2019 1:25 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy (Oxygen)
Replies: 1
Views: 51

Re: Ionization Energy (Oxygen)

Nitrogen has a half-full p shell so that is more stable than adding one e- in the case of ox. since ox. has 4 e- in the p shell there is more e- repulsion and more of an incentive to lose one e- in order to achieve a more stable half-full p shell
by Rida Ismail 2E
Tue Nov 05, 2019 1:19 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Magnetic Quantum numbers
Replies: 4
Views: 162

Re: Magnetic Quantum numbers

The magnetic quantum is the orbital that an e- occupies. If let's say it is in the p block than it can be in 1 of 3 orbitals. I don't think it matters directly which orbital we stick it in, but just as long as we follow all of the rules (Hund, Aufbau, Pauli)
by Rida Ismail 2E
Tue Nov 05, 2019 1:16 pm
Forum: Lewis Structures
Topic: When to draw Resonance Structures
Replies: 14
Views: 179

Re: When to draw Resonance Structures

I believe that if we have to draw the lewis structure regardless of where we will have to draw resonance. But if you are talking about the formal charge when you are addressing the most stable state, then yes you always draw the most stable unless it states otherwise.
by Rida Ismail 2E
Tue Nov 05, 2019 1:15 pm
Forum: Lewis Structures
Topic: Midterm
Replies: 3
Views: 68

Re: Midterm

I do not believe it will be. We have not covered it in class yet.
by Rida Ismail 2E
Tue Nov 05, 2019 1:14 pm
Forum: Octet Exceptions
Topic: Radicals
Replies: 2
Views: 75

Re: Radicals

I was talking to my TA about the same question and he said that you assign it to the more electronegative atom. He was not 100% positive though so I would double-check with Dr. Lavelle
by Rida Ismail 2E
Mon Oct 28, 2019 9:47 am
Forum: Administrative Questions and Class Announcements
Topic: Midterm Time
Replies: 1
Views: 21

Midterm Time

Is the midterm going to take place during the class period on Wednesday?
by Rida Ismail 2E
Mon Oct 28, 2019 9:43 am
Forum: Administrative Questions and Class Announcements
Topic: Class canceled ?
Replies: 1
Views: 42

Re: Class canceled ?

If classes are cancelled I'm pretty sure that means that class will not be held...so no one will be there. So I don't think we go.
by Rida Ismail 2E
Wed Oct 23, 2019 4:21 pm
Forum: Lewis Structures
Topic: Valence e in d block
Replies: 5
Views: 129

Re: Valence e in d block

I believe that zinc has only 2 electrons in its valence shell because of the 4s shell. So its valence shell of 4s is filled making it have only 2 valence electrons.
by Rida Ismail 2E
Wed Oct 23, 2019 4:19 pm
Forum: Octet Exceptions
Topic: Max number of valence e
Replies: 6
Views: 75

Re: Max number of valence e

I am not sure of the max number. I know that the max number is 8 for elements with only s and p orbitals because they do not have room for more electrons. But as the atomic number increases it is possible to have more than 8 electrons.
by Rida Ismail 2E
Tue Oct 22, 2019 8:24 am
Forum: Trends in The Periodic Table
Topic: Metals, Nonmetals, Metalloids
Replies: 5
Views: 90

Re: Metals, Nonmetals, Metalloids

A periodic table is given to us on each exam along with equations and constants. Therefore as long as u know when the line of metalloids are you will be able to figure out which questions are metals, metalloids, and nonmetals.
by Rida Ismail 2E
Tue Oct 22, 2019 8:20 am
Forum: Trends in The Periodic Table
Topic: 2nd Ionization Energy
Replies: 7
Views: 61

Re: 2nd Ionization Energy

The first ionization energy is how much energy is needed to remove an electron from a neutral atom. The second ionization energy is how much energy is needed to remove an electron from a positively charged atom, meaning it has already lost an electron. It would take more energy to remove a second o...
by Rida Ismail 2E
Tue Oct 22, 2019 8:16 am
Forum: Administrative Questions and Class Announcements
Topic: Week 4 homework problems
Replies: 5
Views: 67

Re: Week 4 homework problems

Our homework and units aren't broken up by week. The quantum unit is multiple weeks long so the page with the key concepts and hw problems apply to this week, too. Hope this helps! Did Lavelle say that we can use chemical bond problems for this weeks homework? I believe we finished the quantum worl...
by Rida Ismail 2E
Tue Oct 22, 2019 8:14 am
Forum: Trends in The Periodic Table
Topic: Periodic Table trends
Replies: 11
Views: 447

Re: Periodic Table trends

The biggest difference is their shape and their ability to hold e-. The s-orbital can only hold 2 e-. The p-orbital can only only 6 e-. The d-orbital can only hold 10 e-. The f-block can hold 14 e-. In the ground state of an atom, the electrons must fill up all spots in lower energy levels before mo...
by Rida Ismail 2E
Tue Oct 22, 2019 8:10 am
Forum: Quantum Numbers and The H-Atom
Topic: f- orbitals?
Replies: 4
Views: 74

Re: f- orbitals?

I think its good to know how to do e- configurations for f. The concept it good to know because there could possibly be conceptual questions on e- configurations, but since he said we didn't need to know e- configurations for f orbitals for the exam there probably won't be a directed questions on f ...
by Rida Ismail 2E
Tue Oct 22, 2019 5:54 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: unpaired electrons
Replies: 2
Views: 35

Re: unpaired electrons

You need to follow Aufbau, Hund and Pauli principles to find the amount of unpaired electrons. You look for the outermost shell or the energy level and see how many electrons it constants. For the p orbital, if it contains 1 then there is 1 unpaired. If it contains 2 then there is 2 unpaired. If it ...
by Rida Ismail 2E
Tue Oct 22, 2019 5:46 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence Shell Electron Configuration
Replies: 2
Views: 30

Re: Valence Shell Electron Configuration

How I like to remember it is of you make it across a period, right to left, then it is not in the valance electron. These electrons would be considered core eelcteons and anything after that is the valence. This rule does not apply for nobel gases. With nobel gases the out sheel is filled so the val...
by Rida Ismail 2E
Wed Oct 16, 2019 10:46 pm
Forum: *Shrodinger Equation
Topic: Electron Spin
Replies: 2
Views: 43

Re: Electron Spin

both electrons have the same amount of spin, it is just opposite. Dr. Lavelle did not address the reason why they spin, but you need to know that they do. And the evidence for the spin is shown in the Stern and Gerlach Experiment. Another key component is that in order for e- to pair up they have to...
by Rida Ismail 2E
Wed Oct 16, 2019 10:41 pm
Forum: General Science Questions
Topic: Chemistry Community Registration
Replies: 2
Views: 83

Re: Chemistry Community Registration

you could also possibly try creating a new account completely. I would talk to Dr. Lavelle because I know there is a certain way he wants out usernames to be but possibly if you do create a new account just add a period somewhere to differentiate.
by Rida Ismail 2E
Wed Oct 16, 2019 10:38 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Incorrect Atom Model
Replies: 3
Views: 55

Re: Incorrect Atom Model

the part that makes the uncertainty greater than the speed of light is the fact that the atom is contained. If the atom is not contained the uncertianty drops making it realistic. So the specific point that makes it unrealistic is confining an e- to a certain place
by Rida Ismail 2E
Wed Oct 16, 2019 10:36 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: How would you explain this?
Replies: 3
Views: 140

Re: How would you explain this?

In order to get the lines on the emission spectra you must ensure that the exact wavelength of light is emitted. so for a line to show up you know exactly the wavelength that was addressed.
by Rida Ismail 2E
Wed Oct 16, 2019 10:34 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Magnetic Quantum number [ENDORSED]
Replies: 4
Views: 107

Re: Magnetic Quantum number [ENDORSED]

The easiest way to make sure you got all the number is to make sure that their is a one value for the about of subshells present in the orbital (aka if you are dong the d orbital there should be 5 numbers: 2,1,0,-1,-2)
by Rida Ismail 2E
Wed Oct 16, 2019 10:32 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: the fourth number?
Replies: 4
Views: 52

Re: the fourth number?

the 4th number does not tell you anything about the placement of the e-. It only states that in the pairs of e- in orbitals the e- must be spinning in different directions. So in order to fill the e- shell in an orbital the arrows (representing 1/2 and -1/2) must go in the opposite directions
by Rida Ismail 2E
Wed Oct 16, 2019 10:28 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital Conceptual Question
Replies: 1
Views: 70

Re: Orbital Conceptual Question

1. no electrons can be inside the nucleus. it is not possible. So the sphere only refers to the space around the nucleus. And yes, the orbital is the place in which that electron in its ground state would be found. There is no way to pinpoint the exact location, but this gives a very good estimate o...
by Rida Ismail 2E
Sun Oct 13, 2019 8:48 pm
Forum: Properties of Light
Topic: Quick question on equations
Replies: 5
Views: 50

Re: Quick question on equations

I remember being told that we will always be given an equation sheet. as someone else already mentioned, the equation sheet will not give us what the variable is and therefore we will have to know what those mean
by Rida Ismail 2E
Sun Oct 13, 2019 8:44 pm
Forum: Properties of Electrons
Topic: N increase
Replies: 2
Views: 11

Re: N increase

in order to move up in energy levels the e- must also have increasing energy. therefore the higher the n the higher the energy in the electron
by Rida Ismail 2E
Sun Oct 13, 2019 8:43 pm
Forum: DeBroglie Equation
Topic: Deriving De Broglie's Equation
Replies: 2
Views: 47

Re: Deriving De Broglie's Equation

how i did it is i used the equations E=pc, E=hv, and c=hv:

you first convert c=hv to v=c/λ
Then substitute v=c/λ into the v in E=hv giving you E=h(c/λ)
then set E=pc equal to E=h(c/λ), giving you pc=h(c/λ)
the c cancel
giving you p=h/λ
solve for λ
λ=h/p
by Rida Ismail 2E
Wed Oct 09, 2019 6:46 pm
Forum: SI Units, Unit Conversions
Topic: Fundamentals L35
Replies: 5
Views: 139

Fundamentals L35

hey guys in fundamentals L.35 it talks about trying to find the mass of iron needed to produce 2.50t of NaBr. what is the t and what is the conversion factor to grams?
by Rida Ismail 2E
Wed Oct 09, 2019 4:13 pm
Forum: SI Units, Unit Conversions
Topic: Sig Fig Help! [ENDORSED]
Replies: 6
Views: 151

Re: Sig Fig Help! [ENDORSED]

if there is a decimal place, like in the situation of 1.0003 you would start counting from the left and you would start counting from the first non-zero number. so in 1.0003 there are 5 sig figs but in 0.00007 there is only 1 sig fig if there is no decimal place, like 67, you would start counting fr...
by Rida Ismail 2E
Wed Oct 09, 2019 4:00 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G21 [ENDORSED]
Replies: 2
Views: 112

Fundamentals G21 [ENDORSED]

Hey guys. I'm struggling with G21.

A solution is prepared by dissolving 0.500 g of KCL, 0.500g of K2S and 0.500 of K3PO4 in 500.mL of water. What is the concentration in the dinal solution of (a) potassium ions;(b) sulfide ions?

Can anyone please help me solve this?
by Rida Ismail 2E
Wed Oct 09, 2019 3:42 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G13
Replies: 6
Views: 1553

Re: Fundamentals G13

When I solved for the moles of the diluted solution I got .005 (.05M/.1L) but I am confused as to why you multiply it by two. I know that it is the moles for NH4NO3 and that there are two nitrogen atoms but what is the reasoning for multiplying the moles by two. Is it that in the ratio there are 2N...
by Rida Ismail 2E
Tue Oct 08, 2019 5:48 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Fundamentals E17
Replies: 2
Views: 161

Fundamentals E17

does anyone know how to complete Fundamentals E17?
by Rida Ismail 2E
Tue Oct 08, 2019 11:40 am
Forum: Empirical & Molecular Formulas
Topic: Test 1 Outline Question
Replies: 4
Views: 111

Re: Test 1 Outline Question

505312292 wrote:Hi, can I ask where you got the Test 1 Outline from? Thanks!

It is in every email that he has sent so far. You can also find it on his website.
by Rida Ismail 2E
Tue Oct 08, 2019 11:38 am
Forum: Empirical & Molecular Formulas
Topic: empirical to molecular formula [ENDORSED]
Replies: 9
Views: 397

Re: empirical to molecular formula [ENDORSED]

Ok, so your question confuses me just a bit. But I want to give you a list of steps which should hopefully answer your question. If the question gives you an empirical formula or you just calculated the empirical formula, you would then need to calculate the empirical formula of the empirical formul...
by Rida Ismail 2E
Thu Oct 03, 2019 10:12 pm
Forum: Significant Figures
Topic: All students read this sig fig post [ENDORSED]
Replies: 133
Views: 17457

Re: All students read this sig fig post [ENDORSED]

Evamae Bayudan 1B wrote:Will we be penalized for putting extra significant figures?


Yes, I believe we will because sig figs determine the amount of precision that a number contains. If we have too many or too few sig figs, our precision for that number will be off
by Rida Ismail 2E
Thu Oct 03, 2019 10:03 pm
Forum: Significant Figures
Topic: Practical Application of Sig Figs?
Replies: 3
Views: 53

Re: Practical Application of Sig Figs?

One example that I can think of is working in a lab. When you are diluting a solution, for example, you want to make sure that you have the correct number of sig figs so that you can measure out the correct amount of concentrated solution and add it to the correct amount of water to produce the desi...
by Rida Ismail 2E
Thu Oct 03, 2019 9:55 pm
Forum: Significant Figures
Topic: Sig Figs on the Test
Replies: 3
Views: 77

Re: Sig Figs on the Test

Usually, in calculations of molar mass, you use the molar mass of each element to the hundredths decimal place, and add them all together. This does not count when determining the overall number of sig figs
by Rida Ismail 2E
Thu Oct 03, 2019 9:52 pm
Forum: SI Units, Unit Conversions
Topic: Discussion Credit
Replies: 7
Views: 148

Re: Discussion Credit

I believe that attending discussion is mandatory, so attendance probably gets taken into account and averaged with the 5 hw problems and chem community posts/answers when determining your overall average for the discussion portion of the grade.
by Rida Ismail 2E
Thu Oct 03, 2019 9:49 pm
Forum: Empirical & Molecular Formulas
Topic: 100 gram Method?
Replies: 9
Views: 126

Re: 100 gram Method?

The only reason 100g is used is that it is simple to think of a percentage as a number out of 100. Therefore, you can assume that 1% is equivalent to 1g. If given mass composition, you are able to easily use the percentages given and assume that that percentage was taken from a 100g sample

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