Atomic Structure, Electronic Configuration, and Quantum Numbers – General Chemistry Study Guide

Q1. A clorofila absorve a luz nas energias de 3,056 x 10-19 J fóton-1 e 4,414 x 10-19 J fóton-1. A que cor correspondem essas absorções?

Background

Topic: Spectroscopy and Light Absorption

This question tests your understanding of the relationship between photon energy and the color of light absorbed, using the electromagnetic spectrum.

Key formula:

$E = \frac{hc}{\lambda}$

Where:

• $E$ = energy of the photon (in joules)

• $h$ = Planck's constant ($6.626 \times 10^{-34}$ J·s)

• $c$ = speed of light ($3.00 \times 10^8$ m/s)

• $\lambda$ = wavelength (in meters)

Step-by-Step Guidance

1. Start by rearranging the formula to solve for wavelength: $\lambda = \frac{hc}{E}$

2. Plug in the values for $h$ and $c$ for each energy value to calculate the corresponding wavelength.

3. Convert the wavelength from meters to nanometers ($1 \text{ m} = 10^9 \text{ nm}$).

4. Compare the calculated wavelengths to the visible spectrum to determine the color associated with each absorption.

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Q2. A ação protetora do ozônio na atmosfera vem através da reação do ozônio com radiação UV na faixa de comprimento de onda de 230 a 290 nm. Qual é a energia, em quilojoules por mol, associada com radiação nesta faixa de comprimento de onda?

Background

Topic: Energy of Photons and Moles

This question tests your ability to convert wavelength to energy and then scale up to the energy per mole of photons.

Key formula:

$E = \frac{hc}{\lambda}$

$E_{\text{mol}} = E_{\text{photon}} \times N_A$

Where:

• $E_{\text{photon}}$ = energy per photon

• $N_A$ = Avogadro's number ($6.022 \times 10^{23}$ mol-1)

Step-by-Step Guidance

1. Choose a wavelength within the given range (e.g., 230 nm or 290 nm).

2. Convert the wavelength from nanometers to meters.

3. Calculate the energy per photon using $E = \frac{hc}{\lambda}$.

4. Multiply the energy per photon by Avogadro's number to get the energy per mole.

5. Convert the result from joules to kilojoules.

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Q3. a) Qual é o comprimento de onda associado aos elétrons viajando a um décimo da velocidade da luz? b) A que velocidade um feixe de prótons deve ser acelerado para exibir um comprimento de onda de De Broglie equivalente a 10,0 pm?

Background

Topic: De Broglie Wavelength

This question tests your understanding of the wave-particle duality and how to calculate the wavelength of particles using their mass and velocity.

Key formula:

$\lambda = \frac{h}{mv}$

Where:

• $\lambda$ = wavelength (in meters)

• $h$ = Planck's constant ($6.626 \times 10^{-34}$ J·s)

• $m$ = mass of the particle (in kg)

• $v$ = velocity of the particle (in m/s)

Step-by-Step Guidance

1. For part (a), use the mass of the electron and a velocity equal to $0.1c$ ($c = 3.00 \times 10^8$ m/s).

2. Plug these values into the De Broglie equation to solve for $\lambda$.

3. For part (b), use the mass of the proton and set $\lambda = 10.0$ pm ($1 \text{ pm} = 10^{-12}$ m).

4. Rearrange the De Broglie equation to solve for $v$: $v = \frac{h}{m\lambda}$.

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Q4. Responda as questões abaixo e justifique suas respostas:

Background

Topic: Quantum Numbers and Orbitals

This question tests your understanding of the rules and restrictions for quantum numbers ($n$, $l$, $m$) and their physical meaning.

Key terms:

• $n$ = principal quantum number (energy level)

• $l$ = angular momentum quantum number (subshell)

• $m$ = magnetic quantum number (orientation)

Step-by-Step Guidance

1. Recall the allowed values for each quantum number: $l$$ranges from$0$to$n-1$,$m$ ranges from $-l$ to $+l$.

2. For part (a), check if $n=3$, $l=0$, $m=0$ is a valid set.

3. For part (b), with $n=3$ and $m=1$, determine the possible values of $l$.

4. For part (c), check if $n=2$, $l=2$, $m=2$ is allowed based on the rules.

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Q5. Quando um átomo de cobre perde um elétron para se tornar um íon de Cu+, quais são os possíveis números quânticos do elétron que foi perdido?

Background

Topic: Electronic Configuration and Quantum Numbers

This question tests your understanding of the electron configuration of copper and which electron is lost when forming Cu+.

Key terms:

• Electron configuration of Cu: [Ar] 4s1 3d10

• Quantum numbers: $n$, $l$, $m$, $s$

Step-by-Step Guidance

1. Write the electron configuration for neutral copper.

2. Identify which electron is most likely to be removed to form Cu+.

3. Determine the quantum numbers for the electron removed.

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Q6. Observe o diagrama mostrado abaixo que representa os três primeiros níveis de energia para as três primeiras camadas atômicas. Os níveis de energia são mostrados para um átomo de hidrogênio, à esquerda, e três típicos átomos multieletrônicos, à direita, Li, Na e K, com cada espécie multieletrônica apresentando seu diagrama específico. Diante do conjunto de dados, responda ao que se pede:

Background

Topic: Energy Levels and Electron Configuration

This question tests your understanding of energy level degeneracy, the effect of increasing atomic number, and energetic inversion in multielectronic atoms.

Key concepts:

• Degeneracy: Orbitals with the same energy

• Electrostatic forces: Attraction between electrons and nucleus

• Energy inversion: 4s vs 3d orbitals

Step-by-Step Guidance

1. For part (a), explain why hydrogen's orbitals are degenerate but multielectronic atoms are not.

2. For part (b), discuss how increasing atomic number affects orbital energy, referencing electrostatic attraction.

3. For part (c), explain the energetic inversion between 4s and 3d orbitals in potassium.

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Q7. Qual(is) dos seguintes diagramas de orbitais está(ão) incorreto(s)? Qual dos diagramas corresponde a um estado excitado e qual corresponde ao estado fundamental de um átomo neutro? Explique suas respostas.

Background

Topic: Orbital Diagrams and Electron Configuration

This question tests your ability to interpret orbital diagrams, identify excited and ground states, and recognize incorrect configurations.

Key concepts:

• Hund's rule

• Pauli exclusion principle

• Ground vs excited state

Step-by-Step Guidance

1. Examine each diagram for violations of Hund's rule or the Pauli exclusion principle.

2. Identify which diagram(s) show electrons paired incorrectly or in the wrong order.

3. Determine which diagram represents an excited state (electrons promoted to higher energy levels).

4. Identify the diagram that represents the ground state (lowest energy configuration).

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Q8. Identifique o elemento com a configuração eletrônica no estado fundamental: 1s2 2s2 2p6 3s2 3p6 4s2 3d2. Justifique sua resposta.

Background

Topic: Electronic Configuration and Periodic Table

This question tests your ability to identify elements based on their electron configuration.

Key concepts:

• Electron configuration notation

• Periodic table structure

Step-by-Step Guidance

1. Count the total number of electrons in the configuration.

2. Locate the element with this atomic number on the periodic table.

3. Justify your answer based on the configuration and periodic table position.

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Q9. a) Use a notação spdf para mostrar a configuração eletrônica do iodo. Quantos elétrons o átomo I tem em sua subcamada 3d? Quantos elétrons desemparelhados existem em um átomo de I? b) Indique o número de elétrons de valência em um átomo de bromo. c) Mostre os elétrons de mais energéticos em um átomo de telúrio. d) Dê os elétrons desemparelhados de um átomo de índio. e) Apresente os elétrons em um átomo de prata. É necessário apresentar a configuração eletrônica de todas as espécies.

Background

Topic: Electronic Configuration and Valence Electrons

This question tests your ability to write electron configurations, identify valence electrons, and determine unpaired electrons for various elements.

Key concepts:

• spdf notation

• Valence electrons

• Unpaired electrons

Step-by-Step Guidance

1. Write the full electron configuration for each element using spdf notation.

2. Identify the number of electrons in the specified subshells (e.g., 3d for I).

3. Determine the number of valence electrons for Br.

4. Identify the most energetic electrons for Te.

5. Count the unpaired electrons for In and Ag.

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Q10. Um elemento de número atômico par pode ser paramagnético? (Dica: tente escrever os diagramas orbitais de alguns dos elementos de transição no Período 4. Pesquisar na literatura os conceitos de paramagnético e diamagnético.)

Background

Topic: Magnetism and Electron Configuration

This question tests your understanding of paramagnetism and diamagnetism, and how electron pairing affects magnetic properties.

Key concepts:

• Paramagnetic: Atoms with unpaired electrons

• Diamagnetic: Atoms with all electrons paired

Step-by-Step Guidance

1. Review the definition of paramagnetic and diamagnetic substances.

2. Write orbital diagrams for transition elements with even atomic numbers in Period 4.

3. Check for the presence of unpaired electrons in these elements.

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Q11. As distribuições eletrônicas abaixo correspondem ao estado fundamental de alguns elementos. Identifique-os e explique sua escolha.

Background

Topic: Electronic Configuration and Element Identification

This question tests your ability to identify elements based on their ground-state electron configurations.

Key concepts:

• Ground-state configuration

• Periodic table

Step-by-Step Guidance

1. Count the total number of electrons in each configuration.

2. Match the electron count to the atomic number of the element.

3. Justify your identification based on the configuration and periodic table position.

Try solving on your own before revealing the answer!