Question 1

Which statement best describes the relationship between wavelength ($$\lambda) $$and frequency ($$
u) $$for electromagnetic radiation?

Accepted Answer

As wavelength increases, frequency decreases.

Question 2

A sodium vapor streetlamp emits light at a wavelength of 589 nm. What is the frequency ($$
u) of $$this radiation? (Speed of light $$c = 2.998 	imes 10^8$ m/s)

Accepted Answer

$$5.09 	imes 10$$^{14}$$ Hz

Question 3

Which of the following best explains the photoelectric effect?

Accepted Answer

Electrons are emitted from a metal surface only when the light frequency exceeds a threshold value.

Question 4

What is the energy of a single photon emitted by a laser pointer with a wavelength of 650 nm? ($$h = 6.626 	imes 10$$^{-34}$$ J·s, c = 2.998$$ 	imes $$10^8 m/s)$$

Accepted Answer

$$3.06 	imes 10$$^{-19}$$ J

Question 5

According to the Bohr model, what happens when an electron in a hydrogen atom moves from $$n=5 to$$ $$n=2$$?

Accepted Answer

The atom emits a photon and the electron loses energy.

Question 6

Which equation gives the energy of a photon?

Accepted Answer

$$E = h
u$$

Question 7

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number ($$\ell)$$

Question 8

How many orbitals are present in the $$n=3$$ shell?

Accepted Answer

9

Question 9

Which of the following sets of quantum numbers is valid for an electron in an atom?

Accepted Answer

$$n=2, \ell=1, m_\ell=0, m_s=+\frac{1}{2}$$

Question 10

Which principle states that no two electrons in an atom can have the same set of four quantum numbers?

Accepted Answer

Pauli Exclusion Principle

Question 11

What is the de Broglie wavelength ($$\lambda) of an $$electron moving at $$5.97 	imes 10^6$ m/s? (Mass of electron m = 9.11$$ 	imes $$10^{-31} kg$$, $$h = 6.626 	imes 10$$^{-34}$$ J·s)

Accepted Answer

$$1.22 	imes 10$$^{-10}$$ m

Question 12

Which statement about atomic orbitals is correct?

Accepted Answer

Orbitals in higher shells are larger and have more radial nodes.

Question 13

Which rule explains why electrons fill degenerate orbitals singly before pairing?

Accepted Answer

Hund's Rule

Question 14

For the $$n=4$$ shell, how many possible values of $$\ell$$ are there?

Accepted Answer

4

Question 15

Which of the following best describes the Heisenberg Uncertainty Principle?

Accepted Answer

It is impossible to know both the exact position and momentum of an electron simultaneously.

Question 16

Which electron configuration represents a transition metal cation, Fe$$^{2+}$$?

Accepted Answer

[Ar] $$3d^6$$

Question 17

Which orbital has a nodal plane?

Accepted Answer

2p

Question 18

Why does the 2s orbital have lower energy than the 2p orbital in multi-electron atoms?

Accepted Answer

2s orbital penetrates closer to the nucleus, experiencing less shielding.

Question 19

Which region of the electromagnetic spectrum does the Lyman series of hydrogen emission lines fall into?

Accepted Answer

Ultraviolet

The Quantum Mechanical Model of the Atom: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard