total number of e- = # of dots + 2 x number of lines = 22 + 10 = 32 e-
O = 6 valence e-
Cl3 = 7 valence e- x 3 = 21e-
therefore we have 27e- accounted for.
32 - 27 = 5e-
which element in period 3 has 5 valence electrons? = phosphorus
Search found 22 matches
- Sun May 20, 2018 10:34 pm
- Forum: Lewis Structures
- Topic: HW 3.37
- Replies: 2
- Views: 384
- Sun May 20, 2018 10:26 pm
- Forum: Lewis Structures
- Topic: Chemical Formula Name
- Replies: 3
- Views: 505
Re: Chemical Formula Name
The moderators on this website have already confirmed that we will be given the actual formulas on the test. So we don't need to know how to figure out the formulas by looking at the names :)
- Sun May 20, 2018 10:21 pm
- Forum: Lewis Structures
- Topic: Formal Charge
- Replies: 4
- Views: 654
Re: Formal Charge
# of valence electrons - (number of dots + number of lines) = Formal charge
- Sun May 20, 2018 10:20 pm
- Forum: Lewis Structures
- Topic: 3.39
- Replies: 5
- Views: 702
Re: 3.39
Good news is for the tests we'll be given the actual chemical formulas so we don't have to memorize them :)
- Sun May 20, 2018 10:08 pm
- Forum: Resonance Structures
- Topic: HW problem 3.45
- Replies: 4
- Views: 562
Re: HW problem 3.45
Why when doing the resonance structure can we not give Cl-N a double bond? Or can we? It is technically possible, but we're looking for the lewis structure with the lowest formal charge If you calculate the formal charge of Cl, it comes out as 0, meaning that there is no need to change the electron...
- Sun May 20, 2018 2:28 am
- Forum: Lewis Structures
- Topic: HW 3.39
- Replies: 3
- Views: 454
Re: HW 3.39
3.39 asks you to draw the lewis structures for (a) ammonium chloride, (b) potassium phosphide, and (c) sodium hyphoclorite My first question is will we be expected to know the empirical formula for these on our own? And secondly, for part a for example, why in the lewis structure does NH₄ have a po...
- Sun May 06, 2018 10:32 pm
- Forum: Properties of Light
- Topic: Homework 1.15
- Replies: 2
- Views: 500
Re: Homework 1.15
In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron. I understand in this problem that hydrogen gives us n=1, but to find the other energy levels in the solution it converts the wavelength ...
- Sun May 06, 2018 10:25 pm
- Forum: Properties of Light
- Topic: Question on excited atoms emitting light and Neon signs
- Replies: 2
- Views: 459
Re: Question on excited atoms emitting light and Neon signs
This is really a interesting topic actually so I decided to research and this is what I found. Gases at atmospheric pressure are not good conductors of electricity. So, to pass a current through a gas requires a gas-discharge tube, which is a glass tube with two electrodes sealed through its walls....
- Sun May 06, 2018 10:20 pm
- Forum: Empirical & Molecular Formulas
- Topic: Test 1/ Question 8 [ENDORSED]
- Replies: 6
- Views: 1006
Re: Test 1/ Question 8 [ENDORSED]
here's the answer. All you need to do here is count how many atoms of each element you have on the molecule
- Sun May 06, 2018 10:09 pm
- Forum: Einstein Equation
- Topic: Question 1.25b
- Replies: 2
- Views: 470
Re: Question 1.25b
We're given that the wavelength of light emitted by the Na atoms = 589 x 10^-9 m a) asks for the energy emitted by an excited sodium atom when it generates a photon this deals with photons, which have no mass, therefore we use the equation E = hv and c = vλ E = hv c = vλ so v = c/λ so E = hc/λ now w...
- Sun May 06, 2018 9:54 pm
- Forum: Properties of Light
- Topic: Question on excited atoms emitting light and Neon signs
- Replies: 2
- Views: 459
Question on excited atoms emitting light and Neon signs
So we've encountered several problems in our chem HW where an excited atom will emit a certain light, and we would determine the energy of the photons emitted by the excited atom. Looking at this from an application point of view, do neon light signs do the same kind of thing to emit light? I'm assu...
- Mon Apr 23, 2018 1:27 am
- Forum: Administrative Questions and Class Announcements
- Topic: Weekly Online Discussion Points
- Replies: 2
- Views: 451
Re: Weekly Online Discussion Points
octaviahuang1f wrote:I don't think we need to record it somewhere else, just make sure to post at least three per week haha.
Haha nice :) Thank you!
- Mon Apr 23, 2018 1:05 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Baseball through sensors experiment [ENDORSED]
- Replies: 5
- Views: 656
Re: Baseball through sensors experiment [ENDORSED]
I've read online that motion detectors are small electronic eyes that detect infrared waves—heat waves that radiate from moving objects. When the detector senses an object moving across its field of view—especially warmer objects such as people, animals and cars—it electronically turns on the light...
- Mon Apr 23, 2018 1:00 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Baseball through sensors experiment [ENDORSED]
- Replies: 5
- Views: 656
Re: Baseball through sensors experiment [ENDORSED]
QuincyH1G wrote:Real question, why are you spending so much time in the bathroom?
I guess I think a lot when I do my business xD
Doesn't everybody have that moment when they have an epiphany on the toilet?
p.s. I wish I had a roof toilet
p.p.s. I have a lot of toilet ideas
- Mon Apr 23, 2018 12:56 am
- Forum: Administrative Questions and Class Announcements
- Topic: Weekly Online Discussion Points
- Replies: 2
- Views: 451
Weekly Online Discussion Points
I understand that 30 points total are given through online discussions on chemistry community. 1 point for each topic/post and 3 points max per week. Also I understand that the "deadline" for this is Sunday midnight. My question is, do we get the credits by just posting each week? Or do we...
- Sat Apr 21, 2018 7:27 pm
- Forum: Photoelectric Effect
- Topic: 1.21 [ENDORSED]
- Replies: 2
- Views: 598
Re: 1.21 [ENDORSED]
Just writing what I have on my notes Key Concept: If EMR only had wave properties, then increasing the intensity of the EMR should theoretically eject electron However according to the experiment... Light sources with long wavelengths cannot eject electrons. BUT light sources with short wavelengths ...
- Sat Apr 21, 2018 7:19 pm
- Forum: Limiting Reactant Calculations
- Topic: Question from test 1 [ENDORSED]
- Replies: 4
- Views: 759
Re: Question from test 1 [ENDORSED]
I'm sure we can discuss this since we already discussed test 1 in our discussion section So the calculation would be... Molar Mass of H2 : 2.01588 g/mol Molar Mass of O2 : 31.9988 g/mol Since O2 is the limiting reactant 100.00g H2 / (2 x 2.01588 g/mol) - 100.00g O2 / (31.9988 g/mol ) = mol of H2 lef...
- Sat Apr 21, 2018 6:36 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Baseball through sensors experiment [ENDORSED]
- Replies: 5
- Views: 656
Baseball through sensors experiment [ENDORSED]
This is a little on a tangent, but related to the example Dr. Lavelle gave to us last lecture on throwing a baseball through sensors. Dr. Lavelle explained that the way these sensors work is that there is a constant stream of photons and once something passes through, the stream is broken, which cau...
- Sat Apr 07, 2018 7:16 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3054891
Re: Post All Chemistry Jokes Here
http://i0.kym-cdn.com/photos/images/newsfeed/000/995/634/f9f.png Pre-2012 chemistry joke bruuh :/ Explanation: Uuh (ununhexium) was officially named as Lv (livermorium) in 2012. So sadly we can't make this joke anymore bruuh https://www.nature.com/articles/nchem.2593
- Sat Apr 07, 2018 7:01 pm
- Forum: Student Social/Study Group
- Topic: Class Course Reader?
- Replies: 1
- Views: 634
Class Course Reader?
I understand that there no longer is a course reader for this class, but I did hear that Dr. Lavelle used to have a course reader for the class. Does anybody know about this? And if anybody has it, it is useful?
- Sat Apr 07, 2018 6:58 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 418826
Re: Rusty on High School Chem [ENDORSED]
I didn't take AP Chem in high school and took general chemistry my sophomore year. I've noticed people on this feed saying there are night study sessions at Hedrick-when and where are those at? Thank you. They're all located in Hedrick Hall Room 125, the specific times are on the document I attache...
- Wed Apr 04, 2018 10:06 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Question Regarding Moles
- Replies: 3
- Views: 809
Re: Question Regarding Moles
The way I did is I just went ahead and ignored the (-) sign on F- and calculated as if I would any other problem (like part A B and D) and it gave me the answer (on the back of the textbook). the U in UF6 is Uranium on the periodic table. Figure out the molar mass of both Uranium and Fluorine, then ...