Chemistry 1: Sub-atomic Particles Quiz

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Questions and Answers

What was the overall charge of the atom in Thomson's Plum-Pudding Model?

Electrically neutral (correct)

Variable charge

Negatively charged

Positively charged

Which particle did J.J. Thomson consider to be a fundamental particle?

Electron (correct)

Proton

Neutron

Nucleus

Who discovered radioactivity and coined the term?

Henri Becquerel

Ernest Rutherford

J.J. Thomson

Marie and Pierre Curie (correct)

What significant contribution did Rutherford make regarding atomic structure?

He introduced the concept of a central nucleus. Signup and view all the answers

What experiment did Rutherford use to demonstrate the shortcomings of Thomson's model?

Gold foil experiment Signup and view all the answers

What did J.J. Thomson conclude about cathode rays?

They consist of negatively charged particles. Signup and view all the answers

What experimental method did Robert Millikan use to determine the charge of an electron?

Charged oil droplets. Signup and view all the answers

What was the main feature of Thomson's Plum-Pudding Model?

Electrons were uniformly distributed in a positive matrix. Signup and view all the answers

Which of the following did Thomson conduct in 1897?

Charge-to-mass ratio calculation. Signup and view all the answers

What did the mass-to-charge ratio allow Thomson to determine?

The properties of electrons. Signup and view all the answers

What analogy was used to describe Thomson's Plum-Pudding Model?

Plum pudding dessert. Signup and view all the answers

Which discovery is attributed to J.J. Thomson?

The identification of the electron. Signup and view all the answers

How were electrons thought to be arranged in the Plum-Pudding Model?

Uniformly distributed throughout the atom. Signup and view all the answers

What primarily contributes to the positive charge of an atom?

Protons in the nucleus Signup and view all the answers

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

In fixed, discrete energy levels Signup and view all the answers

What did Rutherford's model imply about the structure of the atom?

It is mostly empty space. Signup and view all the answers

What makes an atom electrically neutral?

Equal numbers of protons and electrons Signup and view all the answers

What were neutrons discovered to be in Chadwick’s experiment?

Electrically neutral particles Signup and view all the answers

What was the target material used in Chadwick’s Beryllium-Paraffin experiment?

Beryllium Signup and view all the answers

What characteristic of neutrons explains why they were not deflected in experiments?

They are electrically neutral. Signup and view all the answers

In Rutherford's Nuclear Model, what happens to the mass of the atom?

Most of it is concentrated in the nucleus. Signup and view all the answers

Study Notes

Discovery of Electrons

J.J. Thomson conducted experiments in 1897 using cathode rays, revealing they could be deflected by magnetic and electric fields, indicating they were composed of charged particles.
Thomson calculated the mass-to-charge ratio of these particles and found they possessed a net negative charge, coining the term "electron" for these subatomic particles.

Robert Millikan's Experiment

Between 1906 and 1914, Robert Millikan used electrically charged oil droplets to determine the charge of a single electron.
Utilized Thomson’s mass-to-charge ratio to calculate the mass of an electron.

J.J. Thomson's Plum-Pudding Model

Proposed in 1904, suggested that atoms consist of a positively charged matrix that holds most of the atom's mass, akin to "pudding."
Negatively charged electrons were embedded within this matrix like "plums" in a pudding, distributed uniformly, yielding an overall electrically neutral atom.
Asserted that electrons were fundamental particles that could not be further divided.

Radiation Discovery

Henri Becquerel discovered that uranium salts emitted a new form of energy.
Marie and Pierre Curie introduced the term "radioactivity" to describe this emission of energy rays.
Ernest Rutherford identified multiple distinct types of radiation emitted by compounds containing uranium and other elements.

Discovery of Protons

Ernest Rutherford's gold foil experiment demonstrated that Thomson's atomic model was inaccurate.
Introduced the nuclear model of the atom in 1911, featuring a dense, positively charged nucleus at its center, containing most of the atom’s mass.

Rutherford's Nuclear Model

Proposed that electrons orbit a central nucleus in fixed energy levels similar to planets around the sun.
Established the concept that atoms are mostly empty space, with orbiting electrons occupying this volume around the nucleus.
Emphasized that the atom remains electrically neutral, as the positive charge of the nucleus balances the negative charge of the electrons.

Discovery of Neutrons

James Chadwick utilized beryllium as a target in experiments, bombarding it with alpha particles and observing a penetrating radiation that was neither electrically charged nor affected by electric/magnetic fields.
Concluded these neutral particles, with a mass slightly greater than protons, are known as neutrons and possess no electrical charge.

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Description

Test your knowledge on the fundamental aspects of sub-atomic particles, particularly focusing on J.J. Thomson's Cathode Ray Experiment. This quiz covers essential concepts in General Inorganic Chemistry as part of Quarter 1 Week 2b. Dive into the world of electrons and discover their significance in atomic theory.