Module 3 Test Flashcards
(140 cards)
What 4 things did early philosophers believe matter was composed of?
Earth, water, air, and fire.
Why did Democritus’s ideas about matter go against other philosophers beliefs?
Because Democritus could not answer the question of “What holds the atoms together?”.
Why were Democritus’s ideas about matter widely rejected?
Aristotle rejected the notion of atoms because it went against his beliefs. Aristotle was very influential at this time so many continued to reject Democritus’s ideas as well.
What was the book A System of Chemical Philosophy published by John Dalton about?
Describes how Dalton revisited and revised Democritus’s ideas and worked to determine the mass ratios of the elements involved in the experiments Dalton conducted.
Who was John Dalton?
John Dalton was a schoolteacher in England that developed the modern atomic theory by reviving and revising Democritus’s ideas by his performed experiments.
Why do you think John Dalton is important in understanding atoms?
Because his modern atomic theory explains that the conservation of mass in chemical reactions is the result of the rearrangement of atoms during the reaction.
What is an atom?
An atom is the smallest particle of matter that retains the properties of the element.
How do we know atoms exist?
Many experiments have been conducted since Dalton’s time to prove that atoms exist.
What is a cathode ray tube for?
It is used to help researchers study the relationship between mass and charge.
What is an electron?
An electron is a negatively charged particle that is a part of all forms of matter.
Who is J.J. Thomson?
J.J. Thomson was the first to identify the first subatomic particle, the electron.
How did J.J. Thomson identify the electron?
He did this by determining the charge-to-mass ratio of the charged particle, then compared that ratio to other known ratios.
Which of Dalton’s theories did J.J. Thomson disprove?
Thomson disproved Dalton’s theories about atoms not being divisible. His discovered proved Dalton incorrect because atoms can be divided into smaller subatomic particles.
What did Ernest Rutherford prove?
Rutherford proved that Thomson’s plum pudding model was incorrect because it did not match the results of his Gold experiment.
What did Rutherford contribute to atomic theory?
His results from the gold experiment proved that an atom has a positive charge and mass contained in the center of the atom.
What did Rutherford discover?
He discovered that atoms have a nucleus and protons/
Who discovered the neutron?
James Chadwick
What are quarks?
The first experimental evidence for subatomic particles, subatomic particles that make up the composition of the structures for protons and neutrons
Who is Henry Moseley and what did he contribute to atomic theory?
He was an English scientist that discovered atomic number, which explains that the number of protons in an atom identifies it as an atom of a particular element.
What does periodicity have to do with how the periodic table is structured?
The periodic table is organized left-to-right and top-to-bottom by increasing atomic number. This pattern of order within the periodic table is called periodicity.
Where is the atomic number listed on an element on the periodic table?
The atomic number is listed to the left or on top of the element’s symbol on the periodic table.
Where is the atomic mass listed on an element on the periodic table?
The atomic mass is listed below the element’s chemical name at the bottom of each element on the periodic table.
What is an isotope?
An isotope is an atom with the same number of protons but different number of neutrons.
What is the law of definite proportions?
A chemical in a compound always contains the same elements in exactly the same proportions by weight or by mass.