question 22
which element is represented by the electron configuration 1s²2s²2p²?
a) he
b) o
c) c
d) be

question 23
what is the element in which at least one electron is in the d - orbital?
a) k
b) ar
c) ca
d) sc

question 24
what is the electron configuration for ga?
a) 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶
b) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p¹
c) 1s²2s²2p⁶3s²3p⁶4s²4d¹⁰4p¹
d) 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p¹

25. in what way does the figure above (a diagram of electron orbitals with 1s, 2s, 2p orbitals and electron spins) illustrate hund’s rule?

26. in what way does the figure above illustrate the pauli exclusion principle?

27. elements of the fourth and higher main - energy levels do not seem to follow the normal sequence for filling orbitals. why is this so?

28. how do electrons create the colors in a line - emission spectrum?

Question

question 22
which element is represented by the electron configuration 1s²2s²2p²?
a) he
b) o
c) c
d) be

question 23
what is the element in which at least one electron is in the d - orbital?
a) k
b) ar
c) ca
d) sc

question 24
what is the electron configuration for ga?
a) 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶
b) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p¹
c) 1s²2s²2p⁶3s²3p⁶4s²4d¹⁰4p¹
d) 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p¹

25. in what way does the figure above (a diagram of electron orbitals with 1s, 2s, 2p orbitals and electron spins) illustrate hund’s rule?

26. in what way does the figure above illustrate the pauli exclusion principle?

27. elements of the fourth and higher main - energy levels do not seem to follow the normal sequence for filling orbitals. why is this so?

28. how do electrons create the colors in a line - emission spectrum?

Accepted Answer

### Question 22
# Explanation:
## Step 1: Calculate total electrons
The electron configuration is $1s^2 2s^2 2p^2$. Sum the exponents: $2 + 2 + 2 = 6$.
## Step 2: Identify element with atomic number 6
Atomic number 6 corresponds to carbon (C). Helium (He) has atomic number 2, oxygen (O) has 8, and the other He is same as first. So the element is C.
# Answer: C) C

### Question 23
# Explanation:
## Step 1: Recall electron configurations
- K (potassium): $1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$ (no d - electrons)
- Ar (argon): $1s^2 2s^2 2p^6 3s^2 3p^6$ (no d - electrons)
- Ca (calcium): $1s^2 2s^2 2p^6 3s^2 3p^6 4s^2$ (no d - electrons)
- Sc (scandium): $1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^1$ (has a d - electron)
## Step 2: Determine the correct element
Scandium (Sc) has at least one electron in the d - orbital.
# Answer: D) Sc

### Question 24
# Explanation:
## Step 1: Recall gallium's atomic number
Gallium (Ga) has an atomic number of 31.
## Step 2: Analyze electron configuration rules
The electron configuration should follow the Aufbau principle. The correct order of filling is $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^1$. Let's check the number of electrons: $2+2 + 6+2+6 + 10+2+1=31$, which matches Ga's atomic number. Option A has too many electrons, option B has incorrect order (4s fills before 3d is full? No, 3d fills after 4s but in Ga, 3d is full before 4p), option C has incorrect orbital (4d instead of 3d).
# Answer: D) $1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^1$

### Question 25
# Explanation:
## Step 1: Recall Hund's rule
Hund's rule states that electrons in the same sub - level (orbital type) will occupy empty orbitals singly before pairing up.
## Step 2: Analyze the figure
In the 2p sub - level (which has 3 orbitals), the electrons are placed in separate orbitals with parallel spins (the up - arrows in separate 2p boxes) before any pairing would occur (and in the 1s and 2s, they are paired as those orbitals can only hold 2 electrons each). So the 2p electrons are in separate orbitals with the same spin, illustrating Hund's rule (electrons fill degenerate orbitals singly first).
# Answer: The 2p electrons occupy separate orbitals with parallel spins (singly - filled before pairing), which shows Hund's rule (electrons in degenerate orbitals fill singly first with same spin).

### Question 26
# Explanation:
## Step 1: Recall Pauli exclusion principle
The Pauli exclusion principle states that no two electrons in an atom can have the same set of four quantum numbers. In terms of orbital diagrams, this means that in a single orbital, the two electrons must have opposite spins (represented by up and down arrows).
## Step 2: Analyze the figure
In the 1s and 2s orbitals (which can each hold 2 electrons), the two electrons in each of these orbitals have opposite spins (one up, one down). This illustrates the Pauli exclusion principle as it shows that within an orbital, electrons have opposite spins (can't have same spin in same orbital).
# Answer: In the 1s and 2s orbitals, electrons have opposite spins (up - down), showing that no two electrons in an orbital have the same spin (Pauli exclusion principle: max 2 electrons per orbital with opposite spins).

### Question 27
# Explanation:
## Step 1: Recall energy level overlap
For elements in the fourth and higher main - energy levels, the energy levels of different orbitals start to overlap. For example, the energy of the 4s orbital is lower than the energy of the 3d orbital initially (Aufbau principle: fill 4s before 3d), but as we move to higher energy levels (n = 4,5, etc.), the energy difference between orbitals of different principal quantum numbers (n) and angular momentum quantum numbers (l) becomes smaller.
## Step 2: Explain the consequence of overlap
When the energy levels of orbitals from different main - energy levels (e.g., 4s and 3d, 5s and 4d, etc.) are close in energy, electrons can fill orbitals in a different order than the simple "n - first" order because the energy of an orbital is determined by both n and l. So the normal sequence (filling orbitals in order of increasing n) is disrupted because the energy of orbitals from higher n (but lower l) can be lower than orbitals from lower n (but higher l) in some cases (e.g., 4s < 3d, 5s < 4d, etc. initially, and then as electrons fill, the energy of 3d becomes lower than 4s for transition metals).
# Answer: Because energy levels of orbitals from different main - energy levels (e.g., 4s & 3d, 5s & 4d) overlap in energy. So electrons fill orbitals based on energy (not just n), leading to a different filling order than the simple "n - based" normal sequence.

### Question 28
# Explanation:
## Step 1: Recall electron energy states
Electrons in an atom are in specific energy levels (ground state). When an atom absorbs energy (e.g., heat, electricity), electrons can move from the ground state to higher - energy (excited) states.
## Step 2: Explain emission of photons
When these excited electrons return to lower - energy (ground or lower excited) states, they release the excess energy in the form of photons. The energy of a photon is given by $E=h
u=\frac{hc}{\lambda}$, where $h$ is Planck's constant, $
u$ is frequency, $c$ is speed of light, and $\lambda$ is wavelength. Different energy transitions (between different energy levels) correspond to different wavelengths of light. Visible wavelengths correspond to different colors. So when electrons move from higher to lower energy levels, they emit photons of specific energies (colors) that form the line - emission spectrum.
# Answer: Electrons absorb energy, move to excited states. When they return to lower energy states, they emit photons with energy (and thus wavelength/color) corresponding to the energy difference between the levels, creating the line - emission spectrum.

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QUESTION IMAGE

Question

Explanation:

Question 22

Step 1: Calculate total electrons

Step 2: Identify element with atomic number 6

Step 1: Recall electron configurations

Step 2: Determine the correct element

Step 1: Recall gallium's atomic number

Step 2: Analyze electron configuration rules

Answer:

Question 23