Q: A photon has a frequency of $7.5 \times 10^{15}\ \mathrm{Hz}$. What is its energy in joules? ($h = 6.63 \times 10^{-34}\ \mathrm{J\cdot s}$)

$5.0 \times 10^{-18}\ \mathrm{J}$

Q: What is the de Broglie wavelength (in nm) of a 2.9 g Ping-Pong ball traveling at 27 mph? ($1\ \mathrm{lb} = 0.454\ \mathrm{kg}$, $1\ \mathrm{mile} = 1609\ \mathrm{m}$, $h = 6.63 \times 10^{-34}\ \mathrm{J\cdot s}$)

$1.89 \times 10^{-23}\ \mathrm{nm}$

Q: If the wavelength of light is $495\ \mathrm{nm}$, what is its frequency? ($c = 3.00 \times 10^8\ \mathrm{m/s}$)

$6.1 \times 10^{14}\ \mathrm{Hz}$

Question 1

Which of the following statements best explains why the first ionization energy of Be is higher than that of Ca?

Accepted Answer

Be's electrons are closer to the nucleus with less shielding, making them harder to remove.

Question 2

Given the isotopes $^{18}\mathrm{F}$, $^{24}\mathrm{Na}$, and $^{79}\mathrm{Br}$, which isotope has the greatest number of neutrons?

Accepted Answer

$^{79}\mathrm{Br}$

Question 3

A sample of chlorine contains two isotopes: $^{35}\mathrm{Cl}$ (75.53%, mass = 34.969 amu) and $^{37}\mathrm{Cl}$ (24.47%, mass = 36.966 amu). What is the average atomic mass of chlorine?

Accepted Answer

$35.45\ \mathrm{amu}$

Question 4

Which of the following ions is isoelectronic with $\mathrm{Ne}$?

Accepted Answer

$\mathrm{F}^-$

Question 5

What is the molar mass of $\mathrm{SO}_3$?

Accepted Answer

$80.07\ \mathrm{g/mol}$

Question 6

How many atoms are present in 3.14 g of copper ($\mathrm{Cu}$)? (Atomic mass of Cu = 63.55 g/mol, $N_A = 6.022 	imes 10^{23}\ \mathrm{mol}^{-1}$)

Accepted Answer

$2.98 	imes 10^{22}$

Question 7

Which quantum number set is NOT possible for an electron in an atom?

Accepted Answer

$n=2,\ l=2,\ m_l=0,\ m_s=+1/2$

Question 8

Calculate the wavelength (in nm) of light emitted when an electron in a hydrogen atom falls from $n=4$ to $n=2$. ($R_H = 2.178 	imes 10^{-18}\ \mathrm{J}$, $h = 6.63 	imes 10^{-34}\ \mathrm{J\cdot s}$, $c = 3.00 	imes 10^8\ \mathrm{m/s}$)

Accepted Answer

$486\ \mathrm{nm}$

Question 9

Which atomic theory principle is violated if two electrons in the same atom have identical sets of quantum numbers?

Accepted Answer

Pauli Exclusion Principle

Question 10

What is the maximum number of electrons that can be accommodated in an $f$ sub-shell?

Accepted Answer

14

Question 11

A photon has a frequency of $7.5 	imes 10^{15}\ \mathrm{Hz}$. What is its energy in joules? ($h = 6.63 	imes 10^{-34}\ \mathrm{J\cdot s}$)

Accepted Answer

$5.0 	imes 10^{-18}\ \mathrm{J}$

Question 12

Which of the following species are isoelectronic? (Select the correct pair.)

Accepted Answer

$\mathrm{F}^-$\ and\ $\mathrm{Al}^{3+}$

Question 13

Which element would you expect to have the highest first ionization energy: $\mathrm{Na}$ or $\mathrm{Cl}$? Why?

Accepted Answer

$\mathrm{Cl}$, because its electrons are closer to the nucleus with less shielding.

Question 14

What is the de Broglie wavelength (in nm) of a 2.9 g Ping-Pong ball traveling at 27 mph? ($1\ \mathrm{lb} = 0.454\ \mathrm{kg}$, $1\ \mathrm{mile} = 1609\ \mathrm{m}$, $h = 6.63 	imes 10^{-34}\ \mathrm{J\cdot s}$)

Accepted Answer

$1.89 	imes 10^{-23}\ \mathrm{nm}$

Question 15

Which of the following electron configurations is NOT possible?

Accepted Answer

$2p^7$

Question 16

If the wavelength of light is $495\ \mathrm{nm}$, what is its frequency? ($c = 3.00 	imes 10^8\ \mathrm{m/s}$)

Accepted Answer

$6.1 	imes 10^{14}\ \mathrm{Hz}$

Question 17

Which of the following has the largest atomic radius?

Accepted Answer

$\mathrm{Se}^{2-}$

Question 18

What is the minimum number of valence electrons that an element in group 3A must have?

Accepted Answer

3

Question 19

Which of the following transitions in a hydrogen atom would emit the highest energy photon?

Accepted Answer

$n=2$\ to\ $n=1$

Atomic Structure, Isotopes, Quantum Numbers, and Periodic Trends: General Chemistry Study Notes

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