Quantum Mechanics 2 Flashcards Preview

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Flashcards in Quantum Mechanics 2 Deck (21)
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1
Q

When atoms combine to form molecules:

A

They attempt to achieve the lowest energy level

2
Q

In covalent binding:

A

Two single atomic orbitals combine to become a molecular orbital

3
Q

S-s-sigma bonding

A

When two s orbitals combine to create a. Ew orbital that contains both electrons

4
Q

p-p-sigma Bonding

A

Crates a lower energy orbital energy than the single p orbital as well as a higher energy sigma orbital; occurs when two p orbitals overlap; plus and minus wavefunction only combine with the like signs

5
Q

s-p-sigma bonding

A

When s and p orbitals combine; s can only have a positive wave function to combine with the positive part of the p orbital

6
Q

p-p-pi bonding

A

Not rotation symmetric: but symmetric about a plane; when two of the orbitals like pz and py approach each other along the x axis

7
Q

There are a maximum of three covalent bonds that are allowed between two atoms:

A

One p-p-sigma bonds (px-px-sigma)

Two p-p-pi bonds (py-py-pi;pz-pz-pi)

8
Q

Bond order

A

Bond order = (# of e- in bonding MO- # of e- in antibonding MO)/2

9
Q

Molecules with paired electrons are:

A

Diamagnetic and do not interact with a magnetic field

10
Q

Molecules with unpaired electrons are:

A

Paramagnetic and interact with a magnetic field

11
Q

Two properties of electromagnetic radiation

A

Amplitude
Periodicity
They are described by wavelength, wave number, and frequency

12
Q

Frequency (v)

A

Number of waves that pass a given point in time;

v = c/wavelength; c = 3.0x10^8 m/s

13
Q

Wavelength

A

The distance from crest to crest on adjacent waves

14
Q

Wave number

A

The number of waves per unit distance, so it has the units reciprocal to distance cm^-1

Wave number = 1/wavelength

15
Q

Energy of a photon

A

Ep = hv

16
Q

Amount of energy absorbed or emitted by a molecules

A

dEm = Ep = hv

17
Q

Adsorption

A

If Em is positive, the photon is absorbed by the molecule

18
Q

Emission

A

If Em is negative, the photon is emitted by the molecule

19
Q

Doppler effect

A

An o next approaching an observer with speed v, while emitting radiation of wavelength y, seems to be emitting from [1-(v/c)]y rather than from y

20
Q

Zeeman effect

A

The presence of a magnetic field will shift the energy levels between which transition occurs

21
Q

Stark effect

A

An electrical field can shift spectral bands