Search found 31 matches

by Shione Nakahara 1F
Sun Jun 10, 2018 9:48 pm
Forum: Bronsted Acids & Bases
Topic: Oxoacids
Replies: 4
Views: 189

Re: Oxoacids

Oxoacids more readily lose H+ if resulting anion is stabilized by electron withdrawing atoms which delocalize and stabilize the negative charge.
by Shione Nakahara 1F
Sun Jun 10, 2018 9:42 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of an acid
Replies: 14
Views: 512

Re: Strength of an acid

As you go down the group of the periodic table, acidity increases with the decrease of electronegativity (since the size of the atom increases). The smaller the atom, the shorter the bond and thus harder for them to dissociate in water. In my notes from class it says that HF<HCl<HBr<HI which goes fr...
by Shione Nakahara 1F
Sun Jun 10, 2018 9:28 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong or weak acids/ bases
Replies: 6
Views: 396

Re: Strong or weak acids/ bases

Most acids are weak acids that dissociates incompletely. These acids have higher pKa than strong acids which release all there H+ when dissolved in water. Likewise, a weak base is a base that does not ionize fully in water and also has a lower pH compared to strong bases.
by Shione Nakahara 1F
Sun Jun 10, 2018 9:21 pm
Forum: Lewis Acids & Bases
Topic: Strong Acids
Replies: 4
Views: 204

Re: Strong Acids

In my notes I have HF,HCl<HBr<HI. (less acidic to more acidic)
by Shione Nakahara 1F
Sun Jun 10, 2018 9:19 pm
Forum: Lewis Acids & Bases
Topic: Weak vs strong acids [ENDORSED]
Replies: 7
Views: 348

Re: Weak vs strong acids [ENDORSED]

The strength of an acid determines its ability or tendency to lose a H+. A strong acid completes ionizes in a solution while a weak acid only partially dissociates. Stronger acids have a smaller pKa.
by Shione Nakahara 1F
Sun Jun 03, 2018 5:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs
Replies: 7
Views: 185

Re: Lone pairs

Bonding pairs take up less space because they are farther away from the central atom and is controlled by the sharing atoms, while a lone pair is closer to the nucleus and repels more strongly.
by Shione Nakahara 1F
Sun Jun 03, 2018 5:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Transition Metal Valence Electrons
Replies: 3
Views: 159

Re: Transition Metal Valence Electrons

It usually helps to draw out the electron configuration diagram. For example, for Ti, its electron configuration is [Ar]4s^2 3d^2 so it would make sense for it to have 4 valence electrons from the outermost 4s electrons and the 3d electrons.
by Shione Nakahara 1F
Sun Jun 03, 2018 4:59 pm
Forum: Hybridization
Topic: strength of sigma and pi bonds
Replies: 10
Views: 355

Re: strength of sigma and pi bonds

Yes, a sigma bond is stronger than a pi bond. This is because the length of a sigma bond is shorter than a pi bond, and it takes more energy to break a sigma bond.
by Shione Nakahara 1F
Sun May 27, 2018 8:09 pm
Forum: Resonance Structures
Topic: ranking
Replies: 11
Views: 452

Re: ranking

A resonance structure has a greater importance if it fulfills the octet rule and if it has minimum charge separation. In addition, there should be no like charges on atoms that are next to each other.
by Shione Nakahara 1F
Sun May 27, 2018 8:05 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing power
Replies: 10
Views: 464

Re: Polarizing power

The ability of a cation to distort an anion (or pull an electron away) is known as the polarizing power.
by Shione Nakahara 1F
Sun May 27, 2018 7:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance
Replies: 7
Views: 238

Re: Resonance

Delocalization is when electric charge is spread over more than one atom. If there are delocalized electrons, it increases the stability of the system compared to a similar system where electrons are localized.
by Shione Nakahara 1F
Mon May 21, 2018 1:26 am
Forum: Electronegativity
Topic: Electronegativiry vs electron affinity [ENDORSED]
Replies: 4
Views: 263

Re: Electronegativiry vs electron affinity [ENDORSED]

The trends are basically the same, and the trend increases as you go across a period and up a group. Electronegativity is how likely the atom will attract electrons, while electron affinity is the amount of energy released when an electron is added to the atom.
by Shione Nakahara 1F
Mon May 21, 2018 1:23 am
Forum: Ionic & Covalent Bonds
Topic: Ionic versus Covalent Bonds [ENDORSED]
Replies: 1
Views: 70

Re: Ionic versus Covalent Bonds [ENDORSED]

Yes, for example, a molecule like NaOH. The Na+ ion is ionically bonded to the OH- ion, but for the OH- ion, the oxygen and hydrogen atoms are covalently bonded together.
by Shione Nakahara 1F
Mon May 21, 2018 1:21 am
Forum: Lewis Structures
Topic: Lewis Structure
Replies: 2
Views: 91

Re: Lewis Structure

I'm not sure if I understood your question correctly, but yes, there can be two pairs of elements sharing a bond in a linear structure like the previous poster said.
by Shione Nakahara 1F
Sun May 13, 2018 11:18 pm
Forum: Trends in The Periodic Table
Topic: electron affinity [ENDORSED]
Replies: 15
Views: 455

Re: electron affinity [ENDORSED]

A lower electron affinity indicates that an atom does not accept electrons as easily.
by Shione Nakahara 1F
Sun May 13, 2018 11:10 pm
Forum: Octet Exceptions
Topic: OCTET RULE [ENDORSED]
Replies: 10
Views: 320

Re: OCTET RULE [ENDORSED]

Octet rule means that when atoms combine to form molecules, they each lose, gain, or share valence electrons until they attain/share eight electrons.
by Shione Nakahara 1F
Sun May 06, 2018 9:37 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions for electron configuration
Replies: 3
Views: 130

Re: Exceptions for electron configuration

For chromium and copper, a completely full or half full d-sublevel is more stable than a partially filled d sub-level, so an electron from the 4s orbital is excited and rises to the 3d orbital.
by Shione Nakahara 1F
Sun May 06, 2018 9:30 pm
Forum: Trends in The Periodic Table
Topic: Trends to Know
Replies: 12
Views: 451

Re: Trends to Know

I think you should know how electron affinity increases from left to right within a period (caused by the decrease in atomic radius) and how electron affinity decreases from top to bottom within a group (caused by the increase in atomic radius).
by Shione Nakahara 1F
Sun May 06, 2018 9:25 pm
Forum: Properties of Light
Topic: The visible spectrum
Replies: 4
Views: 207

Re: The visible spectrum

The main difference between them is that continuous spectrum contains no gaps whereas line spectrum contains many gaps.
by Shione Nakahara 1F
Sun Apr 29, 2018 9:27 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Unpaired Electrons [ENDORSED]
Replies: 7
Views: 330

Re: Unpaired Electrons [ENDORSED]

FInd the elctron configuration first then draw the valence orbitals so you can look for the unpaired electrons.
by Shione Nakahara 1F
Sun Apr 29, 2018 9:22 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: The concept of Orbitals
Replies: 12
Views: 286

Re: The concept of Orbitals

Orbitals are region of space around the nucleus where we can find electrons with the largest probability.
by Shione Nakahara 1F
Sun Apr 29, 2018 9:13 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: How to properly format your answers
Replies: 6
Views: 135

Re: How to properly format your answers

I think Professer Lavelle used half arrows!
by Shione Nakahara 1F
Sun Apr 22, 2018 7:46 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 12
Views: 366

Re: Photoelectric Effect

Yes, the energy of the photon has to overcome the threshhold energy, and any energy of the photon that is left over is converted to kinetic energy of the electron.
by Shione Nakahara 1F
Sun Apr 22, 2018 7:26 pm
Forum: Empirical & Molecular Formulas
Topic: Rounding atomic weight (general question) [ENDORSED]
Replies: 8
Views: 356

Re: Rounding atomic weight (general question) [ENDORSED]

I would use the atomic mass on the periodic table he gives us, and round at the end.
by Shione Nakahara 1F
Sun Apr 22, 2018 7:18 pm
Forum: Molarity, Solutions, Dilutions
Topic: Units - L or mL? [ENDORSED]
Replies: 15
Views: 553

Re: Units - L or mL? [ENDORSED]

Unless the question specifies otherwise, I would do liters
by Shione Nakahara 1F
Sun Apr 15, 2018 9:16 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity [ENDORSED]
Replies: 3
Views: 166

Re: Molarity [ENDORSED]

Assuming equal volume, technically yes. But, the different is negligible.
by Shione Nakahara 1F
Sun Apr 15, 2018 9:10 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Using the uncertainty principle [ENDORSED]
Replies: 2
Views: 145

Re: Using the uncertainty principle [ENDORSED]

Its' not h. It's h bar which is the same thing as h/2pi
by Shione Nakahara 1F
Sun Apr 15, 2018 9:01 pm
Forum: Empirical & Molecular Formulas
Topic: Finding Empirical and Molecular Formula [ENDORSED]
Replies: 6
Views: 369

Re: Finding Empirical and Molecular Formula [ENDORSED]

Count the atoms to get the molecular formula. The empricial formula is the simplified ratio!
by Shione Nakahara 1F
Sun Apr 15, 2018 8:57 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Reactions
Replies: 5
Views: 234

Re: Balancing Chemical Reactions

I usually look for an element that appears only once on both sides of the equation and balance that first :) Make sure the amount of different elements on both sides are equal. But it also might help to balance the polyatomic molecules first!
by Shione Nakahara 1F
Sun Apr 15, 2018 8:49 pm
Forum: DeBroglie Equation
Topic: 1.41 [ENDORSED]
Replies: 3
Views: 168

Re: 1.41 [ENDORSED]

yes, use the de brogile's equation (lambda = h/mv). solve for v the velocity, because you were given the wavelength (lambda= 100picometers) in the problem , and both h (plancks constant) and m (mass of neutron) are constants. :)

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