Atomic Structure and Models Quiz

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Questions and Answers

What is the small positively charged center of the atom called?

Proton bundle

Atom core

Nucleus (correct)

Electron cloud

According to Rutherford's model, how do electrons move around the nucleus?

In fixed orbits (correct)

In circular waves

In elliptical paths

In random directions

What effect do the forces exerted by the nucleus and the centrifugal force have on electrons?

They cause electrons to orbit the nucleus (correct)

They cause electrons to gain energy

They pull the electrons into the nucleus

They cancel each other out

What did the atomic spectra reveal about elements?

They have unique spectral lines Signup and view all the answers

What happens to an electron moving in an orbit according to Maxwell's theory?

It loses energy and spirals into the nucleus Signup and view all the answers

How was the line spectrum of an element obtained?

By heating the element or using electric discharge Signup and view all the answers

What does the term 'negligible mass' refer to in the context of electrons?

Electrons have mass that can generally be ignored compared to that of the nucleus Signup and view all the answers

What primarily constitutes the mass of an atom?

Protons and neutrons in the nucleus Signup and view all the answers

What is the visible part of the light analyzed using an optical analyzer called?

Visible spectrum Signup and view all the answers

What is the primary limitation of the Bohr model regarding electron movement?

It allows for precise measurement of electron speed and location. Signup and view all the answers

Which type of atomic spectrum appears as black lines in a continuous spectrum?

Absorption spectrum Signup and view all the answers

What does Bohr's model suggest about the energy levels of electrons in an atom?

Energy levels are fixed and quantized. Signup and view all the answers

What concept did Bohr introduce to explain the energy levels of electrons?

Quantum numbers Signup and view all the answers

Which statement describes a key feature of Sommerfeld's atomic model compared to Bohr's?

It introduces sub-levels for energy levels. Signup and view all the answers

How many maximum energy levels are there in an atom in its ground state according to Bohr's model?

Seven Signup and view all the answers

What happens to an excited electron after it gains energy?

It returns to its original level, emitting energy as radiation. Signup and view all the answers

What happens to the energy difference between levels as an electron moves away from the nucleus?

It decreases. Signup and view all the answers

How did Sommerfeld modify Bohr’s theory regarding electron orbits?

Orbits were allowed to be oval in shape. Signup and view all the answers

What observation led Bohr to develop his atomic model?

The spectrum produced by heating hydrogen. Signup and view all the answers

According to Bohr's model, what role do centrifugal and attraction forces play in an atom?

They help electrons revolve around the nucleus. Signup and view all the answers

What is a consequence of the Bohr model for electron energy transitions?

Radiation occurs only in the form of individual spectral lines. Signup and view all the answers

What phenomenon did Bohr's model successfully explain?

The hydrogen atom spectrum Signup and view all the answers

What is a quantum in the context of Bohr's atomic model?

The amount of energy gained or lost during an electron's transition. Signup and view all the answers

What is the significance of the new quantum number introduced by Sommerfeld?

It denotes the energy of sub-level orbits. Signup and view all the answers

What equation did Summerfield use to determine the value of the orbital axis length?

K = n - 1 Signup and view all the answers

What describes the wave nature of an electron according to de Broglie?

Every moving body is associated with wave motion. Signup and view all the answers

According to Heisenberg’s uncertainty principle, what is true about an electron's position and velocity?

Both cannot be known at the same time. Signup and view all the answers

What concept was introduced to represent the region where an electron is likely to be found?

Orbital Signup and view all the answers

What is the primary difference between electromagnetic waves and matter waves?

Separation from the moving body Signup and view all the answers

What did Schrödinger's wave equation help to determine?

The allowed energy levels of the electron Signup and view all the answers

What is described as 'electron clouds'?

Areas where the electron has a high probability of being found Signup and view all the answers

How does the speed of matter waves compare to electromagnetic waves?

They travel slower than electromagnetic waves. Signup and view all the answers

What does the principal quantum number (n) indicate?

The distance of the electron from the nucleus Signup and view all the answers

How many electrons can the 3rd energy level hold?

18 Signup and view all the answers

What is the maximum number of sublevels in the 4th energy level?

4 Signup and view all the answers

Which quantum number represents the number of orbitals in an energy sublevel?

Magnetic quantum number (m) Signup and view all the answers

What symbol is assigned to the first sublevel of the first energy level?

1s Signup and view all the answers

What is the value of the subsidiary quantum number (L) for the 4th energy level?

3 Signup and view all the answers

How many directions does the s sublevel have?

1 Signup and view all the answers

What does the formula m = 2l + 1 calculate?

The number of orbitals in a sublevel Signup and view all the answers

How many orbitals are present in the d sublevel?

5 Signup and view all the answers

What is the correct order of energy levels for electronic configuration?

1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s Signup and view all the answers

Which of the following statements reflects Hund's Rule?

No electron pairing occurs until each orbital has one electron. Signup and view all the answers

What are the possible values of the spin quantum number?

+1/2 and -1/2 Signup and view all the answers

What geometric shape do the p orbitals represent?

Dumbbell-shaped Signup and view all the answers

What principle dictates that lower energy sub-levels must be filled first?

Building-up Principle Signup and view all the answers

Which orbitals come after the 3d orbitals in the sequence of electron filling?

5s Signup and view all the answers

How many orbitals does the f sublevel have?

7 Signup and view all the answers

Study Notes

Atomic History

Democritus (400 BC): First to use the term "atom" (indivisible). He theorized that matter could be divided into fundamental units.
Aristotle (350 BC): Proposed that matter was composed of four elements: earth, fire, water, and air.
John Dalton (1800s): Adapted Democritus' theory to create the first modern atomic model.

Dalton's Atomic Model

Atoms are solid spheres.
All atoms of an element have the same properties (size, mass, shape).
Atoms of different elements have different properties.
Atoms combine to form compounds.

J.J. Thomson's Model

Discovered the electron using cathode ray tube experiments.
Proposed an atomic model where negative electrons are embedded in a positively charged sphere (plum pudding model).

Rutherford's Model

Performed gold foil experiments using alpha particles to test Thomson's model.
Results showed most of the atom is empty space, with a dense, positively charged nucleus at the center.
Alpha particles were deflected by the positive nucleus.

Bohr's Model

Based on the observation of hydrogen's spectrum (light emitted when heated).
Proposed that electrons orbit the nucleus in specific energy levels.
Electrons do not radiate energy while in stable orbits.
Electrons can only gain or lose energy by jumping between energy levels.

Sommerfeld's Model

Improved Bohr's model by proposing that electron orbits can be elliptical, not just circular.
Introduced subsidiary quantum numbers to explain the split spectral lines.
Explained that electrons in an orbital can have different energies (sublevels).

Wave Nature of Electron

De Broglie proposed that electrons exhibit wave properties as well as particle properties.
Electrons are considered to exist within orbitals.

Heisenberg's Uncertainty Principle

It's impossible to know both the position and momentum of an electron precisely.

Schrodinger's Model

Developed a wave equation to describe the electron's wave-like behavior in an atom.
Replaced the concept of fixed electron orbits with electron clouds (probability of finding an electron).

Quantum Numbers

Describe the properties of atomic orbitals (e.g., energy level, shape, orientation in space).
- Four types of quantum numbers:
  - Principle Quantum Number (n): Describes the energy level and distance from the nucleus.
  - Subsidiary Quantum Number (l): Defines the shape of the orbital.
  - Magnetic Quantum Number (m_l) : Defines the orientation of the orbital in space.
  - Electron Spin Quantum Number (m_s): Describes the electron spin direction.

Hund's Rule

No electron pairing occurs in a sublevel until each orbital contains one electron (with the same spin direction).

Building-up Principle

Electrons first fill the lower energy levels and orbitals before filling higher ones.

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Description

Test your knowledge on the atomic structure and various atomic models including Rutherford's and Bohr's theories. Understand key concepts such as electron movement, atomic spectra, and the limitations of different models. This quiz covers foundational ideas about the composition and behavior of atoms.