Q: A sodium atom emits light with a wavelength of $$589\ \text{nm}$$ when an electron transitions from a higher to a lower energy level. What is the energy of the emitted photon? ($$h = 6.626 \times 10$$^{-34}$$\ \text{J}\cdot\text{s}$$, $$c = 3.00 \times 10^8$\ \text{m/s})$$

$$3.38 \times 10$$^{-19}$$\ \text{J}$$

Q: Which of the following best explains why $$\text{O}_2 is $$paramagnetic?

$$\text{O}_2$$ has unpaired electrons in its molecular orbitals.

Q: A photon is emitted when an electron in a hydrogen atom transitions from $$n=4 to$$ $$n=2. $$Which equation gives the energy of the emitted photon?

$$E = 2.18 \times 10$$^{-18}$$\ \text{J}\left(\frac{1}{2^2$} - \frac{1}{4^2$}\right)$$

Question 1

Which of the following best explains why the effective nuclear charge ($$Z_{	ext{eff}}) $$experienced by a 3p electron in sulfur is less than the actual nuclear charge ($$Z) of $$sulfur?

Accepted Answer

Because inner-shell electrons shield outer electrons from the full nuclear charge.

Question 2

Which set of quantum numbers is NOT allowed for an electron in an atom?

Accepted Answer

$$n = 2,\ l = 2,\ m_l = 0,\ m_s = +\frac{1}{2}$$

Question 3

Which of the following electron configurations represents a paramagnetic ion?

Accepted Answer

$$[	ext{Ne}]\ 3s^2$\ 3p^5$

Question 4

A sodium atom emits light with a wavelength of $$589\ 	ext{nm}$$ when an electron transitions from a higher to a lower energy level. What is the energy of the emitted photon? ($$h = 6.626 	imes 10$$^{-34}$$\ 	ext{J}\cdot	ext{s}$$, $$c = 3.00 	imes 10^8$\ 	ext{m/s})$$

Accepted Answer

$$3.38 	imes 10$$^{-19}$$\ 	ext{J}$$

Question 5

Which of the following statements about core and valence electrons is correct?

Accepted Answer

Valence electrons are responsible for the chemical properties of an element.

Question 6

Which element has the highest first ionization energy?

Accepted Answer

Neon ($$	ext{Ne})$$

Question 7

Which of the following ions is isoelectronic with argon ($$	ext{Ar}$$)?

Accepted Answer

$$	ext{Cl}^-$$

Question 8

Which of the following best describes the trend in atomic radius across a period from left to right?

Accepted Answer

Atomic radius decreases due to increased effective nuclear charge.

Question 9

Which of the following electron configurations represents the ground state of a transition metal ion with a $$+2$$ charge?

Accepted Answer

$$[	ext{Ar}]\ 3d^6$

Question 10

Which of the following best explains why $$	ext{O}_2 is $$paramagnetic?

Accepted Answer

$$	ext{O}_2$$ has unpaired electrons in its molecular orbitals.

Question 11

Which of the following best describes the bonding in sodium chloride ($$	ext{NaCl}$$)?

Accepted Answer

Ionic bonding with electron transfer from Na to Cl.

Question 12

Which of the following pairs of elements is most likely to form a covalent bond?

Accepted Answer

Carbon and oxygen

Question 13

Which of the following statements about ionic compounds is correct?

Accepted Answer

They have high melting points due to strong electrostatic forces.

Question 14

Which of the following is the correct electron configuration for the $$	ext{Fe}^{3+}$$ ion?

Accepted Answer

$$[	ext{Ar}]\ 3d^5$

Question 15

A photon is emitted when an electron in a hydrogen atom transitions from $$n=4 to$$ $$n=2. $$Which equation gives the energy of the emitted photon?

Accepted Answer

$$E = 2.18 	imes 10$$^{-18}$$\ 	ext{J}\left(\frac{1}{2^2$} - \frac{1}{4^2$}ight)$$

Question 16

Which of the following best explains why magnesium forms a $$2+$$ ion?

Accepted Answer

Magnesium has two valence electrons, which it loses to achieve a noble gas configuration.

Question 17

Which of the following best describes the trend in electronegativity across a period?

Accepted Answer

Electronegativity increases due to increased effective nuclear charge.

Question 18

Which of the following ions is expected to be diamagnetic?

Accepted Answer

$$	ext{O}^{2-}$$

Question 19

Which of the following best explains why the second ionization energy of sodium is much higher than the first?

Accepted Answer

The second electron is removed from a noble gas core, which is much more stable.

Question 20

Which of the following best describes the difference between ionic and covalent bonds?

Accepted Answer

Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.

CH101 EOH Quiz 2 Study Guide: Atomic Structure, Periodic Trends, and Bonding

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