Search found 31 matches

by Louise Zhuang
Fri Dec 07, 2018 4:01 pm
Forum: Identifying Acidic & Basic Salts
Topic: identify base/acid from lewis structure
Replies: 2
Views: 76

Re: identify base/acid from lewis structure

Generally, a molecule with lone pairs on central atom will be electron donor which is Lewis base, and if the central atom has only six valence electrons it’s Lewis acid because it will be electron acceptor.
by Louise Zhuang
Thu Dec 06, 2018 10:45 pm
Forum: Lewis Acids & Bases
Topic: Electron Withdrawing Atoms?
Replies: 1
Views: 36

Electron Withdrawing Atoms?

What is electron withdrawing atoms which delocalize and stablize the negative charge? (What exactly does "withdrawing electron" means? What are some examples of such atoms?)
by Louise Zhuang
Thu Dec 06, 2018 11:58 am
Forum: Bronsted Acids & Bases
Topic: 6th 12.9c
Replies: 1
Views: 37

6th 12.9c

(c) CH3COOH(aq) + NH3(aq) --> CH3CONH2(aq) + H2O(l)
Why isn't it an acid-base reaction?
by Louise Zhuang
Wed Nov 28, 2018 11:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity of CH2Cl2
Replies: 2
Views: 61

Polarity of CH2Cl2

In 6th edition question 4.25, the answer key suggest that CH2Cl2 is polar. But if we draw the lewis structure in which the two Cl atoms are opposite to each other, wouldn't the charge cancel out and make the molecule nonpolar? How do we know which way to draw?
by Louise Zhuang
Wed Nov 28, 2018 10:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: SnCl2
Replies: 2
Views: 104

SnCl2

Why is Sn an exception to the octet rule? (In SnCl2, Sn only has 2 single bonds and a lone pair)
by Louise Zhuang
Wed Nov 28, 2018 10:48 pm
Forum: Bond Lengths & Energies
Topic: Interaction Potential Energy and Polarizability
Replies: 1
Views: 133

Interaction Potential Energy and Polarizability

Could someone explain what is the interaction potential energy and what is polarizability? Is the potential always negative? Why?
by Louise Zhuang
Sun Nov 25, 2018 10:33 pm
Forum: Hybridization
Topic: Test 3
Replies: 7
Views: 134

Re: Test 3

Is test 3 next Friday? Yeah I wonder what will be covered too.
by Louise Zhuang
Sun Nov 25, 2018 10:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angle
Replies: 3
Views: 35

Bond angle

Do we have to remember the exact bond angle of shapes with lone pairs(e.g. bent) or we just have to say less than the bond angle with the respective shape without lone pairs?
by Louise Zhuang
Sun Nov 25, 2018 10:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Naming the Shape
Replies: 16
Views: 210

Re: Naming the Shape

You can remember them by each electron geometries. For instance, start with AX6, which is octahedral in both electron and molecular geometry. Then replace one atom with lone pair(AX5E, which is square pyramidal, etc
by Louise Zhuang
Sun Nov 18, 2018 9:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Resonance Structures and bond angles
Replies: 4
Views: 145

Re: Resonance Structures and bond angles

No, the bond angle is only associated with the molecular shape and number of lone electron pairs.
by Louise Zhuang
Sun Nov 18, 2018 9:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar molecules
Replies: 5
Views: 72

Re: Polar molecules

Your explanation is basically right. The lone pair also has a strong negative charge, and there's nothing at the opposite side to cancel it out, making the molecule polar.
by Louise Zhuang
Thu Nov 15, 2018 11:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis and VSEPR for I3-
Replies: 3
Views: 53

Lewis and VSEPR for I3-

What is the Lewis model and VSEPR formula for I3-?
by Louise Zhuang
Sun Nov 11, 2018 11:32 pm
Forum: Lewis Structures
Topic: Noble Gas Valence Electrons
Replies: 3
Views: 99

Re: Noble Gas Valence Electrons

Because the VSEPR theory predicts that XeF₂ is linear, and Xe needs 3 lone pairs in order to maintain the linear structure of the molecule.
by Louise Zhuang
Sun Nov 11, 2018 11:29 pm
Forum: Lewis Structures
Topic: Poly-atomic Ions
Replies: 2
Views: 84

Re: Poly-atomic Ions

The negative charge goes to the most electronegative atom and the positive charge goes to the least electronegative atom. The position doesn't really matter.
by Louise Zhuang
Sun Nov 11, 2018 11:27 pm
Forum: Lewis Structures
Topic: VSEPR theory
Replies: 1
Views: 50

Re: VSEPR theory

Because bonding e- don't move around as much as lone pair e-, reducing the chance of getting closer to other e- and repel them. They have less energy too.
by Louise Zhuang
Sun Nov 04, 2018 8:54 pm
Forum: Lewis Structures
Topic: What is the maximum oxidation number of chlorine? Why?
Replies: 1
Views: 30

Re: What is the maximum oxidation number of chlorine? Why?

Okay I get it now, it's because Cl reaches noble gas config this way. But it oxidation number the same as number of gained/lost electrons?
by Louise Zhuang
Sun Nov 04, 2018 8:45 pm
Forum: Lewis Structures
Topic: What is the maximum oxidation number of chlorine? Why?
Replies: 1
Views: 30

What is the maximum oxidation number of chlorine? Why?

The answer is +7, but I don't get the reason behind it.
by Louise Zhuang
Thu Nov 01, 2018 2:12 pm
Forum: Trends in The Periodic Table
Topic: Why is ionization energy of oxygen lower than nitrogen?
Replies: 2
Views: 629

Why is ionization energy of oxygen lower than nitrogen?

According to periodic trend, I.E. increases from left to right, but O is lower than N
by Louise Zhuang
Thu Nov 01, 2018 2:06 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: What is the notation for the valence-shell configuration?
Replies: 2
Views: 48

What is the notation for the valence-shell configuration?

Give the notation for the valence-shell confi guration (including the outermost d-electrons) of (a) the alkali metals; (b) Group 15 elements; (c) Group 5 transition metals; (d) “coinage” metals (Cu, Ag, Au).

Can someone explain what does "notation" mean?
by Louise Zhuang
Wed Oct 31, 2018 9:44 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Is electron removed from 3d or 4s first?
Replies: 5
Views: 1706

Is electron removed from 3d or 4s first?

For example, for the element Mn, when forming a +1 ion is electron removed from 3d or 4s orbital first? Why?
by Louise Zhuang
Wed Oct 31, 2018 9:31 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Shielding Question
Replies: 1
Views: 77

Shielding Question

Is the following statements true for multi-electron atoms? Why? -Electrons in an s-orbital are more effective than those in other orbitals at shielding other electrons from the nuclear charge because an electron in an s-orbital can penetrate to the nucleus of the atom. Electrons having l = 2 are bet...
by Louise Zhuang
Sun Oct 28, 2018 9:56 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: nodal/radial planes
Replies: 5
Views: 120

Re: nodal/radial planes

Yes, when the wave function passes zero, its probability density(which is its derivative) is also zero, thus making it a nodal plane.
by Louise Zhuang
Sun Oct 28, 2018 9:52 pm
Forum: *Shrodinger Equation
Topic: H(psi)=E(psi) Equation
Replies: 2
Views: 226

Re: H(psi)=E(psi) Equation

You just need to understand its concept, not actually using it, so I think you should be fine.
by Louise Zhuang
Thu Oct 25, 2018 11:39 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: atomic orbital and molecular orbital?
Replies: 2
Views: 170

atomic orbital and molecular orbital?

What is the difference between electronic transitions in atomic orbitals (atomic spectroscopy) and electronic transitions in molecular orbitals (molecular spectroscopy)?
by Louise Zhuang
Thu Oct 25, 2018 6:48 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Balmer Series?
Replies: 1
Views: 73

Balmer Series?

Can someone explain to me what is Balmer series and what does those lines represents? I kind of know how to use the equation to solve problems but I'm struggling conceptually. (I was working on Q1.57 on 6th edition)
by Louise Zhuang
Sun Oct 21, 2018 11:25 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: About Uncertainty in position
Replies: 3
Views: 140

About Uncertainty in position

What is the minimum uncertainty in the speed of an electron confined to within a lead atom of diameter 350. pm?
Is the uncertainty in position 350. pm in this problem?
by Louise Zhuang
Sun Oct 21, 2018 11:04 pm
Forum: *Shrodinger Equation
Topic: What is probability density?
Replies: 2
Views: 184

What is probability density?

Why is the square of the wavefunction(psi) the probability density? What is it exactly? (I read the textbook but it doesn't make a lot of sense to me...)
by Louise Zhuang
Fri Oct 19, 2018 1:18 am
Forum: DeBroglie Equation
Topic: 6th HW 1.23 What is KeV?
Replies: 5
Views: 108

6th HW 1.23 What is KeV?

What is KeV? When you see it as the unit of energy, do you use E=hv or lamba=h/p?

Problem: 1.23 The y-ray photons emitted by the nuclear decay of a technetium-99 atom used in radiopharmaceuticals have an energy of 140.511 keV. Calculate the wavelength of these y-rays.
by Louise Zhuang
Sun Oct 14, 2018 10:31 pm
Forum: Properties of Light
Topic: 6th Edition homework 1.37 wavelength of protons and neutrons
Replies: 2
Views: 62

6th Edition homework 1.37 wavelength of protons and neutrons

Protons and neutrons have nearly the same mass. How different are their wavelengths? Calculate the wavelength of each particle when traveling at 2.75 = 105 m/s in a particle accelerator and report the difference as a percentage of the wavelength of the neutron. How do you do this without knowing pro...
by Louise Zhuang
Sun Oct 14, 2018 10:24 pm
Forum: Properties of Light
Topic: 6th edition homework 1.13 Rydberg Formula
Replies: 1
Views: 39

6th edition homework 1.13 Rydberg Formula

Use the Rydberg formula for atomic hydrogen to calculate the wavelength of radiation generated by the transition from n = 4 to n = 2.

What is Rydberg formula?
by Louise Zhuang
Thu Oct 11, 2018 10:25 pm
Forum: Properties of Light
Topic: Homework Question 1.3, 6th Edition
Replies: 2
Views: 83

Homework Question 1.3, 6th Edition

Does this happen when the frequency of light decreases? Why?
(c) The extent of the change in the electrical field at a given
point decreases.

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