QUESTION 1 Calculate the wavelength, in nm, of the photon emitted when an electr

Question

QUESTION 1 Calculate the wavelength, in nm, of the photon emitted when an electron in the H atom drops from the n-6 energy level to n 3. Give your answer using 3 significant figures QUESTION 2 Which set of quantum numbers below is not allowed (incorrect)? mi ms or s 3 2 0 10 +½ 00-½ QUESTION 3 Selenium has an electron configuration 1s22s22p63s23p64s23d104p4. Which electrons are considered valence electrons? 3d104p4 4p 4p 1s22s22p63s23p4s23d104p4 4s23d104p4 QUESTION 4 Gallium has an electron configuration 1s22s22p63s23p64s23d104p1. Which electrons are considered valence electrons? 4s23d104p1 4s24p1 1s22s22p63s23p64s23d104p1 4 3d104p1

Explanation / Answer

Q1

WL of photon from n 6 to 3

Apply Rydberg Formula

E = R*(1/nf^2 – 1/ni ^2)

R = -2.178*10^-18 J

Nf = final stage/level

Ni = initial stage/level

E = Energy per unit (i.e. J/photon)

E = (-2.178*10^-18)*(1/3^2 – 1/6 ^2)

E = 1.815*10^-19

For the wavelength:

WL = h c / E

h = Planck Constant = 6.626*10^-34 J s

c = speed of particle (i.e. light) = 3*10^8 m/s

E = energy per particle J/photon

WL = wavelength in meters

WL = (6.626*10^-34)(3*10^8)/(1.815*10^-19)

WL = 0.0000010952 m

to nanometers:

WL = (0.0000010952)(10^9) = 1095.2 nm

Q2.

Recall Pauli Exclusion principle, which states that no two electrons can have the same quantum numbers. That is, each electron has a specific set of unique quantum numbers.

Now, let us define the quantum numbers:

n = principal quantum number, states the energy level of the electron. This is the principal electron shell. As n increases, the electron gets further and further away. "n" can only have positive integer numbers, such as 1,2,3,4,5,... Avoid negative integers, fractions, decimals and zero.

l =  Orbital Angular Momentum Quantum Number. This determines the "shape" of the orbital. This then makes the angular distribution. Typical values depend directly on "n" value. then l = n-1 always. Note that these must be then positive integers, avoid fractions, decimals. Since n can be 1, then l = 1-1 = 0 can have a zero value.

ml = Magnetic Quantum Number. States the orientation of the electron within the subshell. Therefore, it also depends directly on the "l" value. Note that orientation can be negative as well, the formula:

ml = +/- l values, therefore, 0,+/-1,+/- 2,+/-3 ... Avoid fractions and decimals

ms = the electron spin, note that each set can hold up to two electrons, therefore, we must state each spin (downwards/upwards). It can only have two values and does not depends on other values,

ms can cave only +1/2 or -1/2 spins. avoid all other numbers. also, avoid 0.5 or -0.5

then

a is correct

b is correct

c is incorrect, since l = n, 1=1 is not possible

d is correct

e is correct

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