Question

multiple choice (3 points each)
identify the choice that best completes the statement or answers the question.

1. the number of orbitals for the d sublevel is

a. 1 c. 3
b. 5 d. 7

1. which element has the following electron - configuration: 1s²2s²2p⁶3s²3p³

a. oxygen c. sulfur
b. phosphorus d. magnesium

1. if a wave has low frequency, it also has

a. long wavelengths and low energy c. short wavelengths and high energy
b. long wavelengths and high energy d. short wavelengths and low energy

1. how many unpaired electrons are in a phosphorus atom (atomic number 15)?

a. 0 c. 1
b. 2 d. 3

1. how are the frequency and wavelength of light related?

a. they are directly proportional to each other
b. as frequency increases, wavelength decreases and vice versa
c. wavelength is determined by dividing frequency by the speed of light
d. frequency equals wavelength multiplied by the speed of light

1. if three electrons are available to fill three empty 2p atomic orbitals, how will the electrons be distributed in the three orbitals?

a. three electrons cannot enter 2p atomic orbitals
b. three in one orbital, none in the other two ↑↑↑
c. two electrons in one orbital, one in another, none in the third ↑↓↑
d. one electron in each orbital ↑ ↑ ↑

1. which of the following colors of visible light has the longest wavelength?

a. red c. orange
b. blue d. violet

Explanation:

Step1: Recall orbital number of d - sub - level

The number of orbitals in the d - sub - level is 5. So for question 1, the answer is b.

Step2: Analyze electron configuration

For the electron configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{3}\), the total number of electrons is \(2 + 2+6 + 2+3=15\), and phosphorus has an atomic number of 15. So for question 2, the answer is b.

Step3: Understand the relationship between frequency, wavelength and energy

The energy of a wave \(E = h
u=\frac{hc}{\lambda}\), where \(h\) is Planck's constant, \(
u\) is frequency, \(c\) is the speed of light and \(\lambda\) is wavelength. A wave with low frequency has long wavelength and low energy. So for question 3, the answer is a.

Step4: Determine the number of unpaired electrons in phosphorus

The electron configuration of phosphorus (\(P\), atomic number 15) is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{3}\). In the \(3p\) sub - level, there are 3 unpaired electrons. So for question 4, the answer is c.

Step5: Recall the relationship between frequency and wavelength of light

The relationship between the frequency \(
u\) and wavelength \(\lambda\) of light is \(c=
u\lambda\), so as frequency increases, wavelength decreases and vice - versa. So for question 5, the answer is b.

Step6: Apply Pauli's exclusion principle and Hund's rule

When filling atomic orbitals, electrons first fill each orbital singly with parallel spins (Hund's rule). If three electrons are available to fill three empty \(2p\) atomic orbitals, one electron will be in each orbital with parallel spins. So for question 6, the answer is d.

Step7: Know the order of wavelengths of visible light

Among red, blue, orange and violet, red has the longest wavelength in the visible light spectrum. So for question 7, the answer is a.

Answer:

1. b. 5
2. b. Phosphorus
3. a. long wavelengths and low energy
4. c. 3
5. b. As frequency increases, wavelength decreases and vice versa
6. d. One electron in each orbital ↑ ↑ ↑
7. a. Red