Question
What is the maximum number of electrons in energy level n = 4?
A. 8
B. 18
C. 32
D. 50
▶️Answer/Explanation
Markscheme: C
The maximum number of electrons that can occupy an energy level is given by the formula \(2n^2\), where \(n\) is the principal quantum number (the energy level).
For \(n = 4\):
\[2 \times (4)^2 = 2 \times 16 = 32\]
Therefore, the correct answer is C. 32.
Question
What is the correct ground state electron orbital configuration for \(2s^22p^2\)?
▶️Answer/Explanation
Markscheme: A
According to the Pauli Exclusion Principle, no two electrons in an atom can have the same set of four quantum numbers. This means that electrons in the same orbital must have opposite spins. Each orbital can accommodate a maximum of 2 electrons with opposite spins.
\(2 s^2\) represents the electron configuration for the 2s subshell, which can hold up to 2 electrons with opposite spin.
In the case of the \(2 p\) subshell, there are three individual orbitals labeled \(2 p_x, 2 p_y\), and \(2 p_z\). Each of these orbitals can hold up to 2 electrons with opposite spins. Two electrons are in the \(2 \mathrm{p}\) subshell, one in \(2 p_x\) with spin \(\uparrow\) and the other in \(2 p_y\) with spin \(\uparrow\).
To satisfy the Pauli Exclusion Principle, the two electrons in the \(2 p^2\) configuration must have opposite spins and must be placed in different orbitals within the \(2 p\) subshell.
So, the correct distribution is one electron in \(2 p_x\) with spin \(\uparrow\) and the other electron in \(2 p_y\) with spin \(\uparrow\). This ensures that both electrons have unique sets of quantum numbers, complying with the Pauli Exclusion Principle.
Question
Which statement about the electromagnetic spectrum is correct?
A. Infrared light has a shorter wavelength than ultraviolet light.
B. Visible light has a shorter wavelength than ultraviolet light.
C. The frequency of visible light is higher than the frequency of infrared light.
D. The energy of infrared light is higher than the energy of visible light.
Answer/Explanation
Markscheme
C
Examiners report
Question
Which species have the same electron arrangements?
I. \({{\text{O}}^{2 – }}\), \({{\text{F}}^ – }\), Ne
II. \({\text{L}}{{\text{i}}^ + }\), \({\text{N}}{{\text{a}}^ + }\), \({{\text{K}}^ + }\)
III. \({{\text{S}}^{2 – }}\), Ar, \({{\text{K}}^ + }\)
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
Answer/Explanation
Markscheme
B
Examiners report
Question
Ultraviolet radiation has a shorter wavelength than infrared radiation. How does the frequency and energy of ultraviolet radiation compare with infrared radiation?
Answer/Explanation
Markscheme
A