Chapter 3.1: The Atom-From Philosophical Idea to ...



BELL WORK:

Read the following statements, “Young people should not smoke” and “Smoking at a young age may make it more difficult to quit smoking later”. Which of the statements is opinion and which is a theory?

KEY IDEAS:

• Explain the law of conservation of mass, the law of definite proportions, and the law of multiple proportions.

• Summarize the five essential points of Dalton’s atomic theory.

• Explain the relationship between Dalton’s atomic theory and the law of conservation of mass, the law of definite proportions, and the law of multiple proportions.

NOTES:

Greek Thought

Around 400 BC, __________________ proposed the idea that nature’s basic particle is an atom.

In Greek atom means ______________________.

Aristotle, who came after Democritus, said all matter is ______________________.

Most people felt Aristotle was right, but neither idea was based on any __________________.

The Foundation

By the late 1700’s most chemists believed that an element was something that could not be ______________________ down further.

In the 1790’s chemists focused on ______________________ analysis of matter.

This emphasis on quantitative measurement lead them to three ___________________.

Law of Conservation of Mass

Mass is neither created nor destroyed during a ______________________ chemical reaction or physical change.

What we start with we will ______________________ with.

Matter can only be ______________________.

Antoine Lavoisier a French Chemist formed this based on observations of __________________ reactions.

Law of Definite Proportions

A chemical compound contains the same elements in exactly the same ____________________ of masses regardless of the size of the sample or the source of the compound.

Joseph Louis Proust a French Chemist discovered this by analyzing the ____________________ of several compounds.

Law of Multiple Proportions

If two or more compounds are composed of the ______________________ two elements, then a ratio of the masses of one element combined with a certain mass of the other element is always a ratio of a small ______________________ number.

John Dalton

English School ______________________

Felt the previous laws proved the ______________________ of atoms because you could not have the laws without assuming atoms exist.

Many of the thinkers of the time agreed with him but would not waste time to _____________ the basic evidence and model for the atom. (Newton, Boyle)

His model became known by his name and looked like a ______________________.

Dalton’s Principles

1. All ______________________ is made of atoms.

2. Atoms of a given element have ______________________ size, mass, and properties. Atoms of a different element differ in size, mass, and properties.

3. Atoms cannot be ______________________, created or destroyed.

4. Atoms of different elements ______________________ in simple whole number ratios to form chemical compounds.

5. In chemical reactions, atoms are combined, separated, or ______________________.

From Idea to Theory

Dalton took the idea formed by ______________________ and formed a theory based on scientific evidence.

Not all of Dalton’s Principles have held up to ______________________ over the years.

We now know atoms can be subdivided through ______________________ reactions.

We also know that an element can have different ______________________.

REFLECTION:

1. What do we call atoms of the same element, but with different masses?

2. Can new atoms be created from other atoms?

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