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DO NOW Object A at 40ºC and Object B at 80ºC are placed in contact with each other. Which statement describes the heat flow between the objects? 1. Heat.

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Presentation on theme: "DO NOW Object A at 40ºC and Object B at 80ºC are placed in contact with each other. Which statement describes the heat flow between the objects? 1. Heat."— Presentation transcript:

1 DO NOW Object A at 40ºC and Object B at 80ºC are placed in contact with each other. Which statement describes the heat flow between the objects? 1. Heat flows from object A to object B. 2. Heat flows from object B to object A. 3. Heat flows in both directions between the objects. 4. No heat flow occurs between the objects.

2 Williamsburg High School for Architecture and Design Mr. Quinn and Ms. Tom 9/17/13

3 What Do We Already Know? AIM: What are atoms made of?

4 Origins of Atomic Theory Atomic theory was developed by John Dalton in the mid 1800s He used a combination of laws from chemical reactions AIM: What are atoms made of?

5 Origins of Atomic Theory J. J. Thompson developed the first model of the atom Developed from cathode ray tubes “Plum pudding model:” a positive cloud with negative particles in it AIM: What are atoms made of?

6 Origins of Atomic Theory Rutherford came up with the next model of the atom Gold foil experiment Atoms are mostly empty space AIM: What are atoms made of?

7 Origins of Atomic Theory AIM: What are atoms made of?

8 Parts of the Atom ParticleMassCharge Proton1+1 Neutron10 Electron0 AIM: What are atoms made of?

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10 Exploring Atomic Theory Atoms start with a charge of zero. What does that mean for the number of protons and electrons in an atom? They are the same! Each element is identified by a unique atomic number. The atomic number is equal to the number of protons. What is the relationship between the atomic number and the number of electrons? They are the same! AIM: What are atoms made of?

11 Exploring Atomic Theory Do positive and negative charges attract or repel each other? Electrons orbit the nucleus like the earth orbits the sun. Why doesn’t the earth fall into the sun? Electrons don’t fall into the nucleus for the same reason They are orbiting too quickly AIM: What are atoms made of?

12 Exploring Atomic Theory The other number in each box on the periodic table is the atomic mass. For the small elements, what do you notice about its relationship to the atomic number? It is about double If the atomic number is set and electrons don’t have a mass, what makes up the balance? Neutrons What is the relationship between the number of protons and neutrons for most elements? They are about equal AIM: What are atoms made of?

13 Exploring Atomic Theory Do similar charges attract or repel each other? Repel So would a bunch of protons in the nucleus attract or repel each other? Repel It is neutrons that hold them together. AIM: What are atoms made of?

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15 Problem #1 The mass of a proton is approximately equal to the mass of 1. an alpha particle 2. an electron 3. a neutron 4. a positron AIM: What are atoms made of?

16 Problem #2 What is the mass number of a carbon atom that contains six protons, eight neutrons, and six electrons? AIM: What are atoms made of?

17 Problem #3 Which two particles make up most of the mass of a hydrogen-2 atom? 1. electron and neutron 2. electron and proton 3. proton and neutron 4. proton and positron AIM: What are atoms made of?

18 Problem #4 Which statement about one atom of an element identifies the element? 1. The atom has 1 proton. 2. The atom has 2 neutrons. 3. The sum of the number of protons and neutrons in the atom is The difference between the number of neutrons and protons in the atom is 1. AIM: What are atoms made of?

19 Problem #5 What is the charge of the nucleus of an oxygen atom? – AIM: What are atoms made of?


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