Search found 31 matches
- Sun Jun 10, 2018 8:48 pm
- Forum: Lewis Structures
- Topic: Central atom and octet rule?
- Replies: 12
- Views: 3021
Re: Central atom and octet rule?
is there a rule to know when some atoms are okay with having less than 8 electrons? or should we just memorize some of them and hope for the best?
- Sun Jun 10, 2018 5:35 pm
- Forum: Hybridization
- Topic: strength of sigma and pi bonds
- Replies: 10
- Views: 1276
Re: strength of sigma and pi bonds
since pi bonds are caused by side-to-side overlapping where there is much less overlap due to the orbital paths being parallel, they are easier to break than sigma bonds that overlap head-to-head.
- Sun Jun 10, 2018 5:23 pm
- Forum: Hybridization
- Topic: basics of hybridization
- Replies: 18
- Views: 2439
Re: basics of hybridization
also, the only options for hybridization are sp (2 groups), sp^2 (3 groups), sp^3 (4 groups), sp^3d (5 groups), sp^3d^2(6 groups).
- Sun Jun 03, 2018 11:20 pm
- Forum: Lewis Structures
- Topic: Phosphate Lewis structure?
- Replies: 4
- Views: 748
Re: Phosphate Lewis structure?
the atoms in the 3rd row and below on the periodic table can break the octet rule since they have additional orbitals.
- Sun Jun 03, 2018 11:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: Polarizability
- Replies: 7
- Views: 877
Re: Polarizability
the size of the electron cloud is determined by the energy of the atom's electrons, I believe.
- Sun Jun 03, 2018 10:41 pm
- Forum: Sigma & Pi Bonds
- Topic: delocalized and localized pi bond
- Replies: 3
- Views: 11473
Re: delocalized and localized pi bond
Localized electrons exhibit normal behavior, a localized lone pair remains close to one atom, and a localized bond pair travels between two atoms. Resonance hybrids necessarily contain some "abnormal" electrons. In a delocalized pi bond, instead of sticking near one atom, it visits two ato...
- Sun May 27, 2018 7:08 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma and pi
- Replies: 12
- Views: 1572
Re: Sigma and pi
sigma bonds result from the formation of a molecular orbital by the head-to-head overlap of atomic orbitals, and pi bonds result by side-to-side overlap (with p orbitals). pi bonds can only happen when the head to head overlapping of orbitals has also already occurred. however, a sigma bond can happ...
- Sun May 27, 2018 6:56 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR and Lewis
- Replies: 4
- Views: 517
Re: VSEPR and Lewis
first, identify the central atom and its valence electrons. Then, add an electron for each bonding atom, and add or subtract for the charge (- or +) to get the total number of electrons. Divide the total by 2 to find the total number of electron pairs and use that to identify the basic VSEPR shape.
- Sun May 27, 2018 6:44 pm
- Forum: Sigma & Pi Bonds
- Topic: Logic behind Sigma and Pi bonds?
- Replies: 2
- Views: 514
Re: Logic behind Sigma and Pi bonds?
A sigma bond is a covalent bond which is formed by the head on overlap of two atomic orbitals. A Pi bond is a covalent bond which is formed by the side-to-side overlap of two atomic orbitals.Sigma bonds are relatively stronger when compared with pi bonds.There can be only one sigma bond between two ...
- Sun May 20, 2018 9:00 pm
- Forum: Electronegativity
- Topic: Electronegativity difference
- Replies: 3
- Views: 545
Re: Electronegativity difference
if the electronegativity difference is less than 1.5, it's a covalent bond. Larger than that is typically an ionic bond.
- Sun May 20, 2018 8:35 pm
- Forum: Ionic & Covalent Bonds
- Topic: Octet rule
- Replies: 17
- Views: 2366
Re: Octet rule
you can break the octet rule with atoms that are lower than the 3rd row on the periodic table since they have additional d orbitals as well.
- Sun May 20, 2018 8:30 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Which charge is more favorable?
- Replies: 2
- Views: 507
Re: Which charge is more favorable?
I was told the goal is to have all the atoms with a charge between -2 and 2 (so only -1,0,1), so I think having a -1 charge on two atoms would be better than -2 on one.
- Sun May 13, 2018 8:08 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: formal charge equation
- Replies: 3
- Views: 623
Re: formal charge equation
the formal charge equation is VE-LPE-(1/2)BE or valence electrons - lone pair electrons - (1/2) bonded electrons valence electrons refer to the number of electrons in the outermost shell of an electron that can participate in bonding lone pair electrons refer to the number of valence electrons that ...
- Sun May 13, 2018 7:49 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal charge purpose
- Replies: 40
- Views: 7044
Re: Formal charge purpose
yes, you would need to find the most stable bonding of that molecule by making the formal charges of the atoms zero or as close to zero as possible
- Sun May 13, 2018 12:44 pm
- Forum: Lewis Structures
- Topic: octect rule
- Replies: 4
- Views: 648
Re: octect rule
we can break the octet rule when when there are available d or f orbitals (3rd row and below of the periodic table) and to get the most stable bonding (or get the formal charges of the atoms in the molecule closest to zero). I think on the tests, we are required to draw the most stable molecule, and...
- Sun May 06, 2018 7:04 pm
- Forum: Trends in The Periodic Table
- Topic: Trends to Know
- Replies: 12
- Views: 1337
Re: Trends to Know
what would the specific exceptions be or what trend do the exceptions follow? or are they not relevant to what we would need to know for the midterm?
- Sun May 06, 2018 6:59 pm
- Forum: Trends in The Periodic Table
- Topic: Largest in Atomic Radii?
- Replies: 5
- Views: 578
Re: Largest in Atomic Radii?
More protons would lead to a greater nuclear pull and a smaller atomic radius since the greater nuclear charge pulls the electrons closer to the nucleus.
So fewer protons would lead to a lower nuclear pull and a larger atomic radius due to the lower nuclear charge.
So fewer protons would lead to a lower nuclear pull and a larger atomic radius due to the lower nuclear charge.
- Sun May 06, 2018 6:49 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: half full?
- Replies: 5
- Views: 591
Re: half full?
I don't know if I heard this right, but why are half-filled orbitals more stable?
- Sun Apr 29, 2018 4:06 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: What does electron spin actually mean? [ENDORSED]
- Replies: 9
- Views: 3365
Re: What does electron spin actually mean? [ENDORSED]
Electrons have an intrinsic angular momentum known as electron spin. There's two spin states, up (spinning counterclockwise) and down (clockwise), both of which are at the same rate. The Pauli exclusion principle states that these particles cannot have the same quantum numbers. The only way to occup...
- Sun Apr 29, 2018 3:49 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Quantum Number
- Replies: 3
- Views: 564
Re: Quantum Number
The quantum numbers describes the orbitals. The principal quantum number (n) describes the size of the orbital.The angular quantum number (l) describes the shape of the orbital. Since orbitals that have shapes not like a sphere can point in different directions, we have the magnetic quantum number (...
- Sun Apr 29, 2018 3:44 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: The concept of Orbitals
- Replies: 12
- Views: 1063
Re: The concept of Orbitals
A nodal plane is a plane in which the probability of finding an electron is zero.
- Sun Apr 22, 2018 5:07 pm
- Forum: Properties of Light
- Topic: HW Question 1.57
- Replies: 3
- Views: 342
Re: HW Question 1.57
The question usually specifies if it wants it in nm. If it doesn't, I'm sure both answers will get full credit.
- Sun Apr 22, 2018 3:58 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg [ENDORSED]
- Replies: 5
- Views: 757
Re: Rydberg [ENDORSED]
The Rydberg formula is used to predict the wavelength of light resulting from an electron moving between energy levels.
- Sun Apr 22, 2018 3:50 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Problem 1.15 Textbook
- Replies: 6
- Views: 674
Re: Problem 1.15 Textbook
in the solutions manual for the textbook, it says the transition is n1=1 to n2=3. If 1 is considered n(final) since it's an emission of energy, do we have to say the transition is from n1=3 to n1=1 in order to get the answer correct? or is it still correct to answer it like the solution manual?
- Sun Apr 15, 2018 7:26 pm
- Forum: Balancing Chemical Reactions
- Topic: Whole numbers
- Replies: 7
- Views: 893
Re: Whole numbers
Changing subscripts would change the reaction. The only thing that can be changed would be the coefficients but you would have to maintain the ratios of the original formula.
- Sun Apr 15, 2018 7:20 pm
- Forum: Empirical & Molecular Formulas
- Topic: Determining Formulas Based on Molecule
- Replies: 4
- Views: 636
Re: Determining Formulas Based on Molecule
Adding on to this! I'm not sure if it matters, but how do you arrange the elements in a chemical formula? As in, is there an order to put the elements in while answering a question where you're asked to write the molecular and empirical formulas?
- Sun Apr 15, 2018 7:15 pm
- Forum: Limiting Reactant Calculations
- Topic: Reagent vs. Reactant [ENDORSED]
- Replies: 6
- Views: 1373
Re: Reagent vs. Reactant [ENDORSED]
I'm not exactly sure, but I think the terms are used interchangeably. However, I believe a reactant is a substance that is consumed during a chemical reaction whereas a reagent is simply a substance added to cause or test a chemical reaction.
- Sun Apr 15, 2018 7:07 pm
- Forum: SI Units, Unit Conversions
- Topic: Extensive vs. Intensive Properties?
- Replies: 3
- Views: 1908
Re: Extensive vs. Intensive Properties?
An extensive property is one that depends on the size of the object. For example, Dr. Lavelle talked about volume as an extensive property since it's directly proportional to the amount or size of the object that's being described. An intensive property is one that does not depend on the size or amo...
- Sat Apr 14, 2018 11:49 pm
- Forum: Student Social/Study Group
- Topic: Study Group
- Replies: 8
- Views: 997
Re: Study Group
I could totally use the extra practice! Is there a groupme or groupchat of current students who would like to form a group?
- Sat Apr 14, 2018 11:46 pm
- Forum: Empirical & Molecular Formulas
- Topic: Combustion Reaction [ENDORSED]
- Replies: 6
- Views: 637
Re: Combustion Reaction [ENDORSED]
So the combustion element will not be present in the products side of the reaction? it would just be H2O and CO2?
- Sat Apr 14, 2018 10:06 pm
- Forum: General Science Questions
- Topic: Energy (photon) - Energy (remove e-???) [ENDORSED]
- Replies: 4
- Views: 782
Re: Energy (photon) - Energy (remove e-???) [ENDORSED]
I have the same question. To clarify, does the energy of the photon come from the frequency of its oscillations, which the photon then, according to the textbook, "flings off as a packet of electromagnetic radiation of energy (hv)"? So the energy of a single photon is related to the freque...