Explore BrainMass

Modern Quantum Theory

Modern Quantum Theory is the theoretical foundation of physics which helps explain the chemical behavior of matter at both the atomic and subatomic levels. Quantum theory focuses on the application of quantum mechanics within chemical systems, relying on both experimental and theoretical methods.

Today, quantum chemists use many different methods to investigate the quantum nature of chemical phenomena. One such method is spectroscopy, which can calculate and determine the quantization of energy within an atom. Since molecules have discrete energy levels, quantum chemists can use this data to determine the state of atoms, whether they are in the ground state, excited state, or even in transition states when they undergo different chemical reactions. Another popular method is Nuclear Magnetic Resonance Spectroscopy, which exploits the magnetic properties of atomic nuclei. NMR Spectroscopy can determine the structure, chemical environment, and the reaction state of a particular molecule, just by analyzing the properties of its nuclei.

The modern focus of quantum theory in chemistry is the electronic structure of a molecule or crystal, as a molecule’s electronic structure will ultimately determine how it behaves in different conditions, and how it will react with different molecules within different chemical systems.

Thus, studying modern quantum theory in the context of chemical systems is essential in constructing a conceptual framework needed to understand the atomic and subatomic behavior of atoms, molecules, and condensed matter.

Nuclear Chemistry Question

Please see the attachment. i) Give the expression for the energy levels of a nucleus exhibiting collective quadrup vibrations, taking care to explain the symbols used. State the spin and parity of the first excited state expected in a nucleus exhibiting colle quadrupole vibrations and a nucleus exhibiting collective octupo

Chemistry: The Heisenberg Uncertainty Principle

5. The Heisenberg uncertainty principle is represented mathematically as deltax × m*deltav = h/2, where deltax is the uncertainty in the position, deltav is the uncertainty in the velocity and h is Planck's constant divided by 2. Would it be possible to develop an instrument that could determine both the position and velocity

Atomic number and electronic configuration in a new universe

Suppose you take a trip to a distant universe and find that the periodic table there is derived from an arrangement of quantum numbers different from the one on Earth. The rules in that universe are: 1. principal quantum number n = 1, 2, ... (as on Earth); 2. angular momentum quantum number l = 0, 1, 2, ... n - 1 (as on Ear

Ejecting Electrons with Light

The minimum frequency of light needed to eject electrons from a metal is called the threshold. Find the minimum energy needed to eject electrons from a metal with a threshold frequency of 3.27*10^14s^-1. With what kinetic energy will electrons be ejected when this metal is exposed to light with a wavelength of lamda = 245

Uncertainty In Electron Position

Please see the attached file. Also, please show all solution details. Thank you. German physicist Werner Heisenberg related the uncertainty of an object's position (deltax) to the uncertainty in its velocity deltav. The mass of an electron is 9.11 x 10-31 kg. What is the uncertainty in the position of an electron moving at 9

More effective than outer shell electrons in shielding

Please see the attached file for full problem description. 1. Why are inner shell electrons more effective than outer shell electrons in shielding? Why is the energy diagram for multi electron atoms different from that of the hydrogen atom? 2. How many electrons in a single atom can have the following quantum nu

Mercury electrons

1. Mercury-205 has how many protons, neutrons, electrons, and electrons in the 1st quantum shell? 2. In the compound BCl3 which is the more electronegative element? 3. Which has the higher boiling point? 8-carbon alkane that is a straight chain or an 8-carbon alkane that is branched? 4. Which has the higher octane ra

Example Chemistry Review Problems

I'm reviewing for my Chem final and need stuff explained. Please give very in-depth explanations and answers so I can understand how to do it. The first line of the Balmer series occurs at a wavelength of 656.3 nm. What is the energy difference between the two energy levels involved in the emission that results in this spect

Electron Configurations

The general electron configuration for atoms of all elements in Group 5A is ________. ns2np6 ns2np5 ns2np4 ns2np3 ns2np1 -------------------------------------------------------------------------------- Which element has the following electron configuration? [Kr]5s24d105p1 Sn Sb Cd Ga In ------

What is the quantum of light called? (Multiple Choice Questions)

1. What is the quantum of light called? a. the amplitude b. the frequency c. a photon d. the wavelength 2. What is the oxidation number CHANGE for the iron atom in the reaction: 2 Fe2O3(s) + 3 C(s) --> 4 Fe(s) + 3 Co2(g)? a. -6 b. -3 c. +3 d. +6 3. Of the following, which element has the highest first ionization

25 General Chemistry Multiple Choice Questions

1) Which of the following statements is correct for an electron that has the quantum numbers n = 4 and ml = -2? A. the electron may be in a p orbital B. the electron may be in a d orbital C. the electron is in the second principal shell D. the electron must have a spin quantum number ms = + ½ 2) The set of quant

energy level of electrons in atoms

Which of the following is true? A. The 3s level in hydrogen has a lower energy than the3d level in hydrogen. B. The 4s level in multielctron atoms is equal in energy to the 3d level in multielectron atoms. C. The 2s level in multielectron atoms has a greater energy than the 2s level in hydrogen. D. The 2s level in multiele

Potassium iodide in water and bring the volume of solution

#1 You dissolve 12.6352 g of potassium iodide in water and bring the volume of solution to 250.0 ml. What is the molar concentration of KI? #2 What volume of 0.0436 molar hydrochloric acid is required to react with 30.0 ml of 0.0278 molar LiOH? #3 An AM radio station broadcasts using electromagnetic radiation at 1490 kiloh

Determining the number and location of angular and radial nodes

2. For each of the following orbitals, provide a perspective sketch of the orbital in the Cartesian x, y, z coordinate system. Determine the number of angular nodes and the number of radial nodes in the orbital, and describe where those nodes fall. For instance, the 2px orbital has an angular node in the yz-plane. a) 1s b)

Protons and Neutrons in Nucleus

I need some help in determining the number of protons and the number of neutrons in the nucleus of the following atoms and the number of electrons in their first and quantum shells: 10/5B 14/6C 3/2He 40/19K 16/8O

General Chemistry

Of the following, which gives the correct order for atomic radius for Mg, Na, P, Si and Ar? a. Si > P > Ar > Na > Mg b. Ar > Si > P > Na > Mg c. Ar > P > Si > Mg > Na d. Mg > Na > P > Si > Ar e. Na > Mg > Si > P > Ar A tin atom has 50 electrons. Electrons in the ___________ subshell experience the lowest effecti

The Properties of Atoms

Hi, I need some assistance with the following questions: In the Bohr model of the atom, _____. a) electrons travel in circular paths called orbitals b) electrons can have any energy c) electron energies are quantized d) electron paths are controlled by probability e) both a and c The de Broglie wavelength of a bullet

Bohr hydrogen atom- transitions

1) Of the following transitions in the Bohr hydrogen atom, the __________ transition results in the emission of the highest-energy photon. a. n = 3 -> n = 6 b. n = 6 -> n = 3 c. n = 1 ->n = 4 d. n = 6 ->n = 1 e. n = 1 ->n = 6 2) The frequency of elect

Short Answers for general chemistry, mainly related to atoms.

Question 6 True/False 20 points The number of electrons in orbital 5f6 is 5 electons. True False Question 7 Multiple Choice 20 points Beginning at Argon, Ar, the electron configuration of a Copper atom (Cu) is: [Ar]4s24d4 [Ar]4s24p63d3 [Ar]4s23d7 [Ar]3d104s1 Question 8

Spectrum, Quantum Numbers, Orbital Shapes

1. When an electrical discharged is passed through hydrogen gas, a unique four line spectrum is observed. One of the two blue wavelengths is observed at 411 nm. Calculate the frequency of this blue line. {See attachment for multiple choice options} 2. Calculate the engergy if 3 moles of photons are produced if the frequency o

Complex Color Causation

An aqeuous solutino of Ni(No3)2 is green. Addition of aqueous solution Nh3 causes the color of the solution to change blue. If the ethylenediamine is added to the green solution, the color changes to violet. What causes the colors of these complexes? How do these colors relate to the expected positions of these ligands in the sp

Electronic Spectra and Coordination Chemistry

For the isoelectronic series[V(CO)6]-, Cr(CO)6, and [Mn(Co)6]+, does the energy of the metal to ligand charge-transfer bands increase or decrease with increasing charge on the complex? Why?

Octet rule

Elements in the first short period are limited by the octect rule whereas those in the higher period can expand their valence shells. Describe what this means, account for this phenomenon and give an example of each.

Electronic Configuration

Write the electron configurations for Mg and Ar, using both the spdf notation and orbital box diagrams. Describe the relation of the atom's electron configuration to its position in the periodic table. electron configuration for Mg___________ spdf____________________ orbital box diagram: electron configuration for A

Wavelength, Quantum numbers questions

If energy is absorbed by a hydrogen atom in its general state, the atom is excited to a higher energy state. For example, the excitation of an electron from the level with n=1 to the level n=3 requires radiation with a wavelength of 102.6 nm. Which of the following transitions would require radiation of longer wavelength then

Weigh Out, Precipitate, and Electron Problems

40) A student wishes to repair 2.00 liters of 0.100 M KlO3 (molecular mass 214). The proper procedure is to weigh out: a) 42.8 grams of KIO3 and add 2.00 kilograms of H2O a) 42.8 grams of KIO3 and add H2O until the final homogeneous solution has the volume of 2.00 liters b) 21.4 grams of KIO3 and add H2O until the final homog

Orbitals and Quantum number

What is the total number of p electrons in a single (ground state) P atom? Electron configuration of P is [Ne]3s2 3p3