Ch.7 Review

Question 0

Electromagnetic Spectrum?

Answer 0

(Increasing energy/decreasing wavelength)

Gamma Rays , X-rays , UV rays, Visible (VIGBOYR) , Infrared , Microwaves, Radios

Question 1

Electromagnetic radiation?

Answer 1

Ways that energy travels through space

Question 2

Planck?

Answer 2

Energy is quantized & can occur in discrete units of size (small “packets” of energy = quantum)

(D E) = (planck’s constant(h)) (frequency)

Question 3

Albert Einstein?

Answer 3

Electromagnetic radiation quantized. Electromagnetic radiation is a stream of particles called photons.

Ephoton = hv

Question 4

Photocleric Effect?

Answer 4

Study in which the frequency of light was varied to show that no electrons are emitted by a given metal below a specific threshold. But for light with frequency greater than threshold number of electrons emitted increased with increased frequency.

Question 5

Einstein “energy has…”?

Answer 5

Energy has mass. Special theory of relativity.

m= (E)/ (c^2)

Question 6

Energy of photon?

Answer 6

Ephoton = (hc)/ (wavelength)

Question 7

Dual nature of light?

Answer 7

Light has both wave-like and particle-like properties.

Question 8

Louis de Brogile?

Answer 8

Particles have wavelike properties.

(wavelength) =(h)/ (mv)

v= velocity

Question 9

Diffraction?

Answer 9

Light is scattered from a regular array of points or lines. Showed that particles (like electrons) have wavelengths.

Question 10

Emission spectrum?

Answer 10

When H2 receives energy and some H-H bonds break resulting in H atoms becoming excited and releasing this energy by emitting light of various wavelengths.

Question 11

Line Spectrum? Significance?

Answer 11

Hydrogen emission spectrum. Significant because it shows that only certain energies are allowed for the electrons in hydrogen atom. So electron energy in H is quantized.

Question 12

Bohr?

Answer 12

Electrons in a hydrogen atom move around the nucleus only in certain allowed orbitals.

Question 13

Energy level available to the electron in the hydrogen atom?

Answer 13

E = (-2.178 X 10^-18)J(z^2/n^2)

z-nucleur charge
n-orbit radius

Question 14

Important things about Bohr’s model?

Answer 14

Model correctly fits quantized energy of hydrogen atom & postulates only allow certain circular orbitals.

As electrons become more tightly bond energy becomes more neg. because it releases energy.

Question 15

Energy Change in H equation?

Answer 15

DE = (-2.178 x 10^ -18) (1/ nfinal^2)-(1/n initial ^2)

Question 16

Energy required to remove an electron from a hydrogen atom in its ground state?

Answer 16

N final = infinity so

energy required = 2.178 x 10^ -18

Question 17

de Brogile?

Answer 17

Electrons show wave properties.

Question 18

Shroedinger and Shroedinger’s equation?

Answer 18

Electrons are bound to nucleus seem to be a standing wave. Wave functions = orbitals. Can calculate allowed orbitals using Shroedinger’s equation.

Question 19

Heisenberg’s uncertainty principle?

Answer 19

There is a fundamental limitation to just how precisely we can now both the position and momentum of a particle at a given time.

Question 20

Atomic orbitals?

Answer 20

Square of function. Just an electron density map (probability) .

Question 21

Principle quantum number?

Answer 21

n . Givens size and energy of orbital. Greater than 0.

Question 22

Angular momentum quantum number?

Answer 22

l . 0-> (n-1) . 0= s , 1=p , 2= d , 3=f, 4=g .

Question 23

Magnetic quantum number?

Answer 23

ml . Relative orientation of orbital in space.

Question 24

Nodes?

Answer 24

Areas of low probability that separate high probability areas.

Question 25

Degenerates?

Answer 25

Orbitals with the same n value. (only for hydrogen)

Question 26

Electron spin?

Answer 26

Ms (-1/2,1/2)

Question 27

Pauli Exclusion Principle?

Answer 27

In a given atom no two electrons can have the same set of four quantum numbers. So only 2 electrons per orbital with opposite spins!

Question 28

Electron correlation problem? Penetration effect?

Answer 28

Since electron pathways are unknown, electron repulsion cannot be calculated.

S has lower energy than p etc.

Question 29

The aufbau principle?

Answer 29

Electrons added from lowest energy level up.

Question 30

Hund’s rule?

Answer 30

Lowest energy configuration for an atom is one having the maximum number of unpaired electrons allowed by the pauli principle.

Question 31

Periodic trend: Ionization energy?

Answer 31

Increase across a period because of constant shielding and increase in effective nuclear charge. Decreases down a croup because of an increase in shielding which decreases effective nuclear charge.

Question 32

Electron affinity?

Answer 32

Becomes more negative (so it’s easier) across a period because of effective nuclear charge increasing which attracts the electrons and shielding staying constant so no additional repulsion of the electron.

Question 33

Equation relating wavelength and change in energy?

Answer 33

Wavelength = (h * c)/ (D E)