Questions and Answers
Why is Democritus's view of matter considered only an idea, while Dalton's view is considered a theory?
Democritus's idea of matter does not relate atoms to a measurable property, while Dalton's theory can be tested through quantitative experimentation.
Give an example of a chemical or physical process that illustrates the law of conservation of mass.
A glass of ice cubes will have the same mass when the ice has completely melted into liquid water, even though its volume will change.
State two principles from Dalton's atomic theory that have been revised as new information has become available.
Atoms are divisible into smaller particles called subatomic particles. A given element can have atoms with different masses, called isotopes.
What parts of Dalton's atomic theory are illustrated by the reaction 2H2 O2 → 2H2O?
Signup and view all the answers
If 3 g of element C combine with 8 g of element D to form compound CD, how many grams of D are needed to form compound CD2?
Signup and view all the answers
Which law do these data illustrate?
Signup and view all the answers
State the law regarding chemical compounds.
Signup and view all the answers
Calculate the ratio of the masses of nitrogen that combine with oxygen for compound NO.
Signup and view all the answers
Calculate the ratio of the masses of nitrogen that combine with oxygen for compound NO2.
Signup and view all the answers
Calculate the ratio of the masses of nitrogen that combine with oxygen for compound NO4.
Signup and view all the answers
Which law do these data illustrate in relation to nitrogen and oxygen compounds?
Signup and view all the answers
In cathode-ray tubes, the cathode ray is emitted from the negative electrode, which is called the?
Signup and view all the answers
The smallest unit of an element that can exist either alone or in molecules is called what?
Signup and view all the answers
A positively charged particle found in the nucleus is called a(n)?
Signup and view all the answers
A nuclear particle that has no electrical charge is called a(n)?
Signup and view all the answers
The subatomic particles that are least massive and most massive, respectively, are the?
Signup and view all the answers
What property of the cathode ray is shown by various phenomena including its deflection by a magnetic field?
Signup and view all the answers
How would the electrons produced in a cathode-ray tube filled with neon gas compare with those from chlorine gas?
Signup and view all the answers
Is an atom positively charged, negatively charged, or neutral?
Signup and view all the answers
Explain how an atom can exist in a neutral state.
Signup and view all the answers
Before Rutherford's experiment, which illustration of the atom was believed to be correct?
Signup and view all the answers
After Rutherford's experiment, which illustration of the atom was believed to be correct?
Signup and view all the answers
What is the proton known for?
Signup and view all the answers
What is the neutron known for?
Signup and view all the answers
Where is the electron located?
Signup and view all the answers
Study Notes
Democritus vs. Dalton
- Democritus considered matter as indivisible atoms, but his ideas lacked measurable properties.
- Dalton's atomic theory involves quantifiable experimentation, leading to its acceptance as a scientific theory.
Law of Conservation of Mass
- Melting ice cubes exemplify this law, as the mass remains unchanged despite a change in state from solid to liquid (ice to water).
Revisions in Dalton's Theory
- Atoms can be subdivided into subatomic particles like protons, neutrons, and electrons.
- Elements may have isotopes, which are atoms with the same number of protons but different masses.
Water Formation Reaction
- The reaction 2H₂ + O₂ → 2H₂O demonstrates mass conservation, affirming that mass of products equals mass of reactants.
- Illustrates that atoms combine in simple, whole-number ratios and cannot be created or destroyed.
Compound Formation Example
- Combining 3 g of element C with 8 g of D yields compound CD, requiring 16 g of D to form CD₂.
Law of Definite Proportions
- Each chemical compound consists of its elements in fixed mass proportions, regardless of sample source.
Ratios of Nitrogen to Oxygen Compounds
- In compounds such as NO, NO₂, and NO₄, specific mass ratios of nitrogen to 1 g of oxygen illustrate multiple proportions.
Cathode Rays
- Cathode rays are emitted from the cathode (negative electrode) in cathode-ray tubes and consist of negatively charged particles.
Fundamental Particles
- An atom is the smallest unit of an element that retains its properties, consisting of protons, neutrons, and electrons.
- Protons are positively charged particles found in the nucleus.
- Neutrons are neutral particles located in the nucleus alongside protons.
- Electrons are negatively charged and exist in a cloud surrounding the nucleus.
Atomic Charge
- Atoms overall are neutral due to the balance of positive protons and negative electrons.
- The nucleus carries a positive charge, while electrons contribute a negative charge, resulting in electrical neutrality.
Historical Models of the Atom
- Pre-Rutherford, atoms were depicted with electrons embedded in a positive "soup" (Thomson's model).
- After Rutherford's gold foil experiment, the nuclear model was accepted, showing a dense nucleus and surrounding electron cloud.
Electron Location
- Electrons are located in the region outside the nucleus, forming a cloud structure around it, due to their low mass and negative charge.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your understanding of atoms and their role as the building blocks of matter with this flashcard review of Chapter 3. Explore key concepts like Democritus's idea versus Dalton's theory and the law of conservation of mass. Perfect for reinforcing your knowledge in chemistry.
