Search found 35 matches

by Daniel Martinez 1k
Thu Nov 14, 2019 11:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 4
Views: 6

Re: bond angles

Some angles have "less than" because they have lone pairs, which distort the pull that the atoms have on each other.
by Daniel Martinez 1k
Thu Nov 14, 2019 11:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis Structures & VSEPR
Replies: 7
Views: 17

Re: Lewis Structures & VSEPR

Definitely not necessary. However, it can help you know how many lone pairs and bonded pairs there are, which is essential for VSEPR.
by Daniel Martinez 1k
Thu Nov 14, 2019 11:55 pm
Forum: Electronegativity
Topic: Increasing/Decreasing Electronegativity
Replies: 6
Views: 15

Re: Increasing/Decreasing Electronegativity

Electronegativity is the ability of an atom to pull on other atoms. The trend that electronegativity follows is that it increases to the right and up on the periodic table.
by Daniel Martinez 1k
Thu Nov 14, 2019 11:45 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.3
Replies: 3
Views: 10

Re: 2E.3

The lewis structure would have 4 bonded pairs. So, the C would have a bond pair with 2 Fs and 2 Hs. Since there are 4 bonded pairs and no lone pairs, the shape of the molecule is a tetrahedral.
by Daniel Martinez 1k
Thu Nov 14, 2019 11:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: structure ?
Replies: 2
Views: 11

Re: structure ?

Linear molecular shapes arise when there are 2 bonded pairs. If there are zero, three, or four lone pairs attached to the central atom that already has two bonded pairs, the molecule would have a linear shape.
by Daniel Martinez 1k
Thu Nov 07, 2019 6:59 pm
Forum: Ionic & Covalent Bonds
Topic: Polarizability
Replies: 6
Views: 24

Re: Polarizability

Polarizability increases as the charge and the size of the anion increases.
by Daniel Martinez 1k
Thu Nov 07, 2019 6:57 pm
Forum: Ionic & Covalent Bonds
Topic: Bond Strength
Replies: 9
Views: 26

Re: Bond Strength

Ionic bonds are stronger than covalent bonds in a vacuum. However, in water, covalent bonds tend to be stronger.
by Daniel Martinez 1k
Thu Nov 07, 2019 6:49 pm
Forum: Bond Lengths & Energies
Topic: dissociation energy
Replies: 5
Views: 15

Re: dissociation energy

The trend for dissociation energy is that as bond length increases, the dissociation energy decreases.
by Daniel Martinez 1k
Thu Nov 07, 2019 6:46 pm
Forum: Lewis Structures
Topic: Exceptions for the octet rule
Replies: 5
Views: 35

Re: Exceptions for the octet rule

Sulfur is also an exception to the octet rule. I believe it can go up to 12 electrons as it does in SF6.
by Daniel Martinez 1k
Thu Nov 07, 2019 6:43 pm
Forum: General Science Questions
Topic: Week 6 homework problems
Replies: 7
Views: 45

Re: Week 6 homework problems

The homework questions should consist of chemical bonds. Personally, I included 2D material and on.
by Daniel Martinez 1k
Thu Oct 31, 2019 7:33 pm
Forum: Resonance Structures
Topic: Resonance
Replies: 5
Views: 34

Re: Resonance

Yes. Resonant structures are just different ways of drawing the same structure. These structures should still follow the octet rule when being drawn all of these different ways.
by Daniel Martinez 1k
Thu Oct 31, 2019 7:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Hw problem 2A.13
Replies: 4
Views: 25

Re: Hw problem 2A.13

Make sure to remove the electrons from the highest energy orbital. For example Zn: [Ar] 3d^10 4s^2, the electrons would be removed from the 4s orbital since it is the highest energy orbital.
by Daniel Martinez 1k
Thu Oct 31, 2019 7:25 pm
Forum: Octet Exceptions
Topic: Radicals: Homework Problem #2C1
Replies: 8
Views: 33

Re: Radicals: Homework Problem #2C1

NO2- is not a radical. It has 18 electrons, all of which are paired.
by Daniel Martinez 1k
Thu Oct 31, 2019 7:23 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 11
Views: 35

Re: Electronegativity

Electronegativity is the tendency of an atom to pull electrons. Electronegativity follows the same trends as ionization energy (Increases up and to the right).
by Daniel Martinez 1k
Thu Oct 31, 2019 7:18 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 16
Views: 61

Re: Midterm

Everything we have been assigned homework on until 2D. In other words, Fundamentals, Quantum World, & Chemical Bonds (up to 2D).
by Daniel Martinez 1k
Thu Oct 24, 2019 6:31 pm
Forum: Ionic & Covalent Bonds
Topic: Does the Octet Rule apply to Boron?
Replies: 14
Views: 68

Re: Does the Octet Rule apply to Boron?

No, the Octet rule does not apply to Boron bc it is more stable with 6 e-.
by Daniel Martinez 1k
Thu Oct 24, 2019 6:27 pm
Forum: Octet Exceptions
Topic: Octet exception examples
Replies: 9
Views: 74

Re: Octet exception examples

During Wednesday's lecture, he mentioned H, He, Li, and Be as being exceptions to the octet rule because it was very unlikely that they would gain the electrons needed to complete an octet.
by Daniel Martinez 1k
Thu Oct 24, 2019 6:20 pm
Forum: Ionic & Covalent Bonds
Topic: valence electrons
Replies: 6
Views: 49

Re: valence electrons

Sb has the electron configuration [Kr] 4d^10 5s^2 5p^3.
Since the 4th shell is completely filled, we only focus on the electrons from the fifth shell. With that being said, we only have 5 valence electrons in the 5th shell (2 e- from s-shell & 3 e- from p-shell).
by Daniel Martinez 1k
Thu Oct 24, 2019 6:14 pm
Forum: Properties of Electrons
Topic: hw
Replies: 6
Views: 39

Re: hw

Since we covered both quantum and chemical bonds this week, it is fine to turn in hw that includes Quantum.
by Daniel Martinez 1k
Tue Oct 22, 2019 10:38 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Question 1E.7
Replies: 1
Views: 9

Question 1E.7

Can someone explain to me as to why 1E.7 letter B is not considered the ground state electron configuration for N. Thank you. :)
by Daniel Martinez 1k
Thu Oct 17, 2019 10:17 pm
Forum: *Shrodinger Equation
Topic: Nodal Planes
Replies: 6
Views: 22

Re: Nodal Planes

3.
by Daniel Martinez 1k
Thu Oct 17, 2019 10:15 pm
Forum: Administrative Questions and Class Announcements
Topic: Tutoring? [ENDORSED]
Replies: 61
Views: 53563

Re: Tutoring? [ENDORSED]

If you're eligible, I would suggest joining AAP and attending the peer learning sessions. Really helpful!
by Daniel Martinez 1k
Thu Oct 17, 2019 10:14 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg constant
Replies: 3
Views: 18

Re: Rydberg constant

Yes, the Rydberg constant is specific to H atoms.
by Daniel Martinez 1k
Thu Oct 17, 2019 10:11 pm
Forum: Photoelectric Effect
Topic: HW 1B.5
Replies: 8
Views: 57

Re: HW 1B.5

Yes. You have to convert keV to J before starting the problem.
by Daniel Martinez 1k
Thu Oct 17, 2019 12:01 am
Forum: Quantum Numbers and The H-Atom
Topic: QUESTION 1D.23 FROM HW [ENDORSED]
Replies: 2
Views: 36

QUESTION 1D.23 FROM HW [ENDORSED]

"How many orbitals can have the following quantum numbers in an atom:(a)n=2,l=1;(b)n=4,l=2,ml=-2; (c)n=2;(d)n=3,l=2,ml=+1?"

Can someone help me with this question? Thank you.
by Daniel Martinez 1k
Thu Oct 10, 2019 7:49 pm
Forum: Properties of Light
Topic: Waves/Particles
Replies: 14
Views: 103

Re: Waves/Particles

From my understanding, photons show wave-particle duality, meaning that they exhibit properties of being a particle and a wave (frequency, amplitude, wavelength, etc).
by Daniel Martinez 1k
Thu Oct 10, 2019 7:46 pm
Forum: Significant Figures
Topic: Sig Figs on Tests
Replies: 10
Views: 114

Re: Sig Figs on Tests

Here are the rules for sig figs: 1. Non zero digits are significant. 2. Zeros in between other digits are significant. 3. Leading zeros are NOT significant. 4. Trailing decimal zeros are significant. 5. When adding/subtracting, use the fewest number of decimal places. 6. When multiplying/dividing, u...
by Daniel Martinez 1k
Thu Oct 10, 2019 7:43 pm
Forum: Empirical & Molecular Formulas
Topic: Mass Percent Calculations
Replies: 4
Views: 45

Re: Mass Percent Calculations

First, you would need to calculate the molar mass of C7H15NO3. After that, you have to find the molar masses of each element of that molecule. One needs to divide the molar masses of each element by the total molar mass of C7H15NO3 and multiply by 100% to find the mass percentage compositions.
by Daniel Martinez 1k
Thu Oct 10, 2019 7:40 pm
Forum: Student Social/Study Group
Topic: Pen or Pencil for Homework Problems?
Replies: 8
Views: 59

Re: Pen or Pencil for Homework Problems?

I did not read anything regarding us having to use a pen or pencil on hw problems. However, remember to use a pen when it comes to the exams! :)
by Daniel Martinez 1k
Thu Oct 10, 2019 7:38 pm
Forum: Limiting Reactant Calculations
Topic: Test 1 Calculator
Replies: 6
Views: 71

Re: Test 1 Calculator

A lot of graphing calculators these days are programmable and could contain features that may give others an unfair advantage when it comes to the test. By using a scientific calculator, it ensures that every one has an equal chance.
by Daniel Martinez 1k
Thu Oct 03, 2019 5:04 pm
Forum: Balancing Chemical Reactions
Topic: Question L.35 [ENDORSED]
Replies: 6
Views: 79

Re: Question L.35 [ENDORSED]

Does anyone know how to finish this problem after balancing the equations? Thank you!
by Daniel Martinez 1k
Wed Oct 02, 2019 10:39 pm
Forum: Empirical & Molecular Formulas
Topic: QUESTION F.21 HW
Replies: 3
Views: 26

QUESTION F.21 HW

Can someone help me with this question? I've tried it multiple times and can't seem to get the right answer. Thanks in advance!
by Daniel Martinez 1k
Wed Oct 02, 2019 4:51 pm
Forum: Empirical & Molecular Formulas
Topic: QUESTION F3
Replies: 3
Views: 34

QUESTION F3

Question F3 part A asks "(a) Write the formula for nitric acid." Is this a formula that we are already supposed to know? If not, how does one know the formula without actually calculating the empirical/molecular formulas?
by Daniel Martinez 1k
Tue Oct 01, 2019 9:20 pm
Forum: SI Units, Unit Conversions
Topic: Calculator Question
Replies: 13
Views: 119

Re: Calculator Question

The scientific calculators that you are able to use in this class must not be able to graph or be able to be programmed. I paid $15 for mine, so I assume that anywhere from $10-$15 is a reasonable price for a calculator.
by Daniel Martinez 1k
Tue Oct 01, 2019 9:16 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Avogadro's Number [ENDORSED]
Replies: 12
Views: 118

Re: Avogadro's Number [ENDORSED]

Avogadro's number is 6.0221 x 10^23. It is used to find the number of atoms, molecules, or ions in a mole of any substance.

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