Chemistry- The Atomic Spectra

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What occurs when an electron absorbs a quantum of radiation?

The electron emits energy in the form of light.

The electron moves to a lower energy level.

The electron transitions to a higher energy level. (correct)

The electron remains in its ground state.

What is the term used to describe the fixed energy levels that electrons occupy?

Potential wells

Quantum states (correct)

Orbitals

Energy bands

Which statement about the ground state of electrons is true?

Electrons are unstable in the ground state.

Electrons prefer to occupy the highest energy levels.

Electrons in the ground state continuously lose energy.

Electrons in the ground state are in the lowest energy levels. (correct)

What is a quantum jump?

The transition of an electron from one energy level to another. Signup and view all the answers

What happens to an electron when it falls back to a lower energy level?

It emits a quantum of radiation. Signup and view all the answers

Which best describes atomic spectra?

They are unique patterns produced by electrons transitioning between energy levels. Signup and view all the answers

What is the smallest fixed amount of energy required to change an electron’s energy level called?

Quantum of energy Signup and view all the answers

What issue arises if electrons are considered to be stationary outside the nucleus?

They would radiate energy and spiral into the nucleus. Signup and view all the answers

What is the relationship between the energy of a photon and its wavelength?

Shorter wavelength results in higher energy Signup and view all the answers

Which equation correctly expresses the relationship between frequency and wavelength of electromagnetic radiation?

c = wavelength (λ) × frequency (v) Signup and view all the answers

What does the continuous spectrum refer to?

A blend of colors without distinct divisions Signup and view all the answers

Which part of the electromagnetic spectrum is visible to the human eye?

Wavelengths from 400 to 700 nanometers Signup and view all the answers

Planck's equation ΔE=hv relates which two properties of a photon?

Energy and frequency Signup and view all the answers

What type of electromagnetic radiation is primarily used in medical imaging?

X-rays Signup and view all the answers

Which of the following statements about photons is correct?

Photons are massless particles traveling at the speed of light Signup and view all the answers

What occurs when a beam of white light passes through a prism?

It produces a continuous spectrum Signup and view all the answers

What does the angular momentum quantum number (l) describe?

The shape of the orbitals Signup and view all the answers

How many subshells are present in the n = 3 principal shell?

3 Signup and view all the answers

Which subshells can be found in the n = 4 principal shell?

s, p, d, f Signup and view all the answers

What is the maximum number of electrons that a d-subshell can hold?

10 Signup and view all the answers

What characterizes the p-subshell in terms of orbitals?

It consists of 3 orbitals. Signup and view all the answers

What does the magnetic quantum number (ml) indicate?

The orientation of orbitals within a subshell Signup and view all the answers

Which of the following describes how an electron behaves in terms of spin?

Electrons act like tiny bar magnets. Signup and view all the answers

What is the label used to identify the p-subshell?

2p Signup and view all the answers

What happens when white light passes through a substance?

Certain wavelengths are absorbed, creating dark lines in the spectrum. Signup and view all the answers

What characterizes an emission spectrum?

It consists of bright, colored lines on a dark background. Signup and view all the answers

How does Bohr’s model describe the energy levels of electrons in an atom?

Energy levels are discrete and fixed, like steps on a staircase. Signup and view all the answers

What occurs to an electron when it absorbs energy?

It moves to a higher energy level. Signup and view all the answers

Which color is emitted by excited Neon atoms?

Red-orange Signup and view all the answers

What is the relationship between electron transitions and light emission?

Light is emitted when electrons fall from higher to lower energy levels. Signup and view all the answers

What is the appearance of an absorption spectrum?

Distinct dark lines within a continuous spectrum. Signup and view all the answers

Which statement about the quantization of energy in electrons is correct?

Electrons occupy specific energy levels like discrete steps. Signup and view all the answers

How do three electrons in p-orbitals arrange themselves?

Each electron occupies a separate p-orbital. Signup and view all the answers

What is the maximum number of electrons that can occupy a single orbital?

2 Signup and view all the answers

What principle states that two electrons in one orbital must have paired spins?

Pauli exclusion principle Signup and view all the answers

How would you read the electron configuration of helium, which is 2He?

one-s-two Signup and view all the answers

What is the electron configuration for lithium (atomic number 3)?

1s-two, 2s-one Signup and view all the answers

What does noble gas notation simplify in electronic configuration?

The electron configuration of preceding noble gases Signup and view all the answers

In the case of silicon, what accounts for the first 10 electrons in its electron configuration?

The noble gas neon Signup and view all the answers

How are p- and d-orbitals filled according to Hund's rule?

They fill singly before any orbital contains two electrons. Signup and view all the answers

What is the complete electron configuration for silicon?

[Ne]3s23p2 Signup and view all the answers

Which statement best describes the first ionization energy?

It is the energy needed to remove the outermost electron from a neutral atom in gaseous state. Signup and view all the answers

What factor generally causes the first ionization energy to decrease as atomic radius increases?

Greater electron shielding from inner electrons. Signup and view all the answers

Why are all ionization energies considered positive?

Because energy must be absorbed to remove electrons. Signup and view all the answers

How does electron shielding affect the ionization energy of an atom?

It decreases the ionization energy by allowing outer electrons to be more easily removed. Signup and view all the answers

Which best describes the relationship between atomic radius and ionization energy?

As atomic radius decreases, ionization energy generally increases. Signup and view all the answers

What does the term 'endothermic process' imply in the context of ionization energy?

Energy is absorbed to remove an electron. Signup and view all the answers

What happens to the energy required to remove each successive electron in ionization energy?

The energy increases due to increased effective nuclear charge. Signup and view all the answers

Study Notes

Atomic Structure

Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons
Rutherford's model placed the nucleus at the center but couldn't explain electron placement
Issue 1: Stationary electrons would be pulled into the nucleus by electrostatic attraction.
Issue 2: Moving electrons would continuously radiate energy, causing them to spiral into the nucleus, leading to atomic collapse.
Electrons occupy specific fixed energy levels outside the nucleus, known as quantized states.
Electrons do not continuously move or remain stationary.
Electrons sit in discrete energy levels, or orbitals, around the nucleus without losing energy.
Ground state: The lowest energy level where the atom is most stable
Excited state: When an electron absorbs energy it moves to a higher energy level.
Quantum jump: A transition between quantized energy levels with absorption or emission of energy.
A quantum of energy is the smallest fixed amount required to change an electron's energy level.
Emission occurs when an electron moves from higher to lower energy levels, releasing energy of light.
Absorbing light with sufficient energy moves an electron to a higher energy level.
Atomic spectra: The best evidence that electrons are in specific allowed energy levels
The spectrum of colors observed when electrons move between energy levels
Atomic spectra are formed when electrons absorb or emit light (electromagnetic radiation).
Each element produces a unique atomic spectrum.

Electromagnetic Radiation

Electromagnetic radiation behaves as a stream of photons (particles with no mass).
Photons travel at the speed of light (3.00 × 10⁸ m/s).
The energy of a photon is related to its wavelength (λ) and frequency (v).
The shorter the wavelength, the higher the energy of the photons and vice-versa.
Visible light is a type of electromagnetic radiation that humans can see. Wavelengths range from 400 to 700 nm.
Planck's equation: E = hv (E=Energy, h=Planck's constant, v=frequency)
Frequency and wavelength are related by the equation c=vλ, where c is the speed of light.

The Electromagnetic Spectrum

The range of all possible frequencies (and wavelengths) of electromagnetic radiation.
Ranges from radio waves (longest wavelengths) to gamma rays (shortest wavelengths).
This spectrum contains various forms of radiation (radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays).
Types of radiation and their approximate wavelengths, frequencies, and uses:
- Radio waves: Televisions, cell phones
- Microwaves: Satellites, microwave ovens
- Infrared: Toaster ovens, night-vision
- Visible light: Medical imaging
- X-rays: Medical imaging

Atomic Spectra

Continuous spectrum: All visible wavelengths of light in a rainbow-like array. There are no distinct divisions between colours.
Line spectrum: Distinct bright lines on a dark background
Absorption spectrum: A spectrum of dark lines on a continuous spectrum produced when light passes through a substance.
Emission spectrum: A spectrum of bright lines on a dark background when atoms are heated or excited.

Bohr's Model of the Atom

Electrons exist in quantized energy levels (orbits).
Electrons can only change energy levels by gaining or losing a specific amount of energy.
Electrons in an atom orbit the nucleus, like planets orbiting the Sun.
Principal quantum number (n): Determines energy level of an electron.
Each principal energy level contains one or more subshells (s, p, d, or f)
The lowest energy level is closest to the nucleus and has the smallest orbital.
The highest energy level is furthest from the nucleus and has the largest orbital.

Quantum Mechanical Model of the Atom

Electrons do not move in specific orbits, instead they exist in a 3D region of space called an orbital.
The probability of finding an electron at various locations defines an orbital.
Four quantum numbers are used to describe the electron's properties:
- Principal quantum number (n)
- Angular momentum quantum number (l)
- Magnetic quantum number (ml)
- Spin quantum number (ms)

Electronic Configuration

Represents the arrangement of electrons in various energy levels
Uses the Aufbau principle: Electrons occupy the lowest available energy levels first.
Rules: Pauli Exclusion Principle, Hund's Rule
Notation: Example: 1s²2s²2p⁶3s² for Neon

Ionization Energy

The energy required to remove an electron from an isolated gaseous atom in its ground state.
Factors affecting ionization energy:
- Atomic radius
- Electron shielding
- Nuclear charge
  - Larger atomic radius = lower ionization energy
  - Greater nuclear charge = higher ionization energy.
- Subshells (changes in ionization energy values can show differences between subshells)

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your understanding of key concepts in quantum physics, including the behavior of electrons, quantum jumps, and atomic spectra. This quiz covers essential principles and equations that describe the interactions of photons and electrons, making it an excellent review for students of physics.