Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m =...

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Do Now: Solve the following using the correct number of significant figures . 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2 m = 5)6.9 mm / 3 mm =

Transcript of Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m =...

Page 1: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Do Now: Solve the following using thecorrect number of significant figures.

1)7.76 m + 2.1 m =

2)5.750 cg - 1.1 cg =

3)5555 kg + 444 kg =

4)1.23 m x 3.2 m =

5)6.9 mm / 3 mm =

Page 2: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

YWBAT

• Explain how Democritus and John Dalton described atoms

Page 3: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

History of Atomic Theory

http://ed.ted.com/lessons/the-2-400-year-search-for-the-atom-theresa-doud

Page 4: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Do Now:

1.What models have you used?

2.What other models are you aware of?

3.Why do people use models?

Page 5: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

YWBAT

• Explain how Democritus and John Dalton described atoms

• Identify instruments used to observe atoms.• Identify three types of subatomic particles.• Describe the structure of atoms according to

the Rutherford atomic model.

Page 6: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Democritus

•Greek philosopher (460– 370BC)•Among the first to suggest the existence of atoms.

atomos – Greek word for indivisible

•Reasoned that atoms were indivisible and indestructible.

Page 7: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Dalton

• English chemist & school teacher• 1766 – 1864• Used experimental methods to transform

Democritus’ ideas into scientific theory• Studied ratios in which elements combine in

chemical reactions.

Page 8: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Dalton’s Atomic Theory

1. All elements are composed of tiny indivisible particles called atoms.

Atoms of element A

Page 9: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Dalton’s Atomic Theory

2. Atoms of the same element are identical. The atoms of any one element are different from those of any other element.

Atoms of element A

Atoms of element B

Page 10: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Dalton’s Atomic Theory

3. Atoms of different elements can physically mix together or can chemically combine in simple whole-number ratios to form compounds.

Mixture of atoms of elements A and B

Page 11: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Dalton’s Atomic Theory

4. Chemical reactions occur when atoms are separated from each other, joined, or rearranged in different combinations. Atoms of one element are never changed into atoms of another element as a result of a chemical reaction.

Compound made by chemically combining atoms of elements A and B

Page 12: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Dalton’s Atomic Theory

• Do you think all parts of Dalton’s Atomic Theory are still believed to be true today?

Page 13: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Sizing Up The Atom

• A pure copper coin the size of a penny contains about 2.4 x 1022 atoms

24,000,000,000,000,000,000,000 atoms

* Note – Earth’s population is ~ 7 x 109 people

Page 14: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Sizing Up The Atom

• Individual atoms are observable with a Scanning Electron Microscope (SEM).

SEM Pollen grains

Page 15: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Structure of the Atom

Page 16: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

What is in the box?

Page 17: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Subatomic Particles

1.Protons

2.Neutrons

3.Electrons

Page 18: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Electrons

• In 1897, physicist J.J. Thomson discovered the electron.

• Electrons are negatively charged subatomic particles

https://www.youtube.com/watch?v=Rb6MguN0Uj4

Page 19: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Protons

• In 1886, Eugene Goldstein observed a cathode ray tube and found rays traveling in the direction opposite to that of the cathode ray tubes.– He concluded they were composed of positive

particles.– These positively charged subatomic particles are

called protons

Page 20: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Neutrons

• In 1932, James Chadwick confirmed the existence of the neutron.– Neutrons are subatomic particles with no charge

but with a mass nearly equal to that of a proton.

Page 21: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Subatomic Particles

Page 22: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

How are these three subatomic particles (protons, neutrons, and

electrons) put together in an atom?

Page 23: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Plum Pudding Model

• Thompson’s atomic model• Electron’s stuck in a lump of positive

charge, similar to raisins stuck in dough.

Page 24: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Rutherford’s Gold Foil Experiment

• In 1911, Ernest Rutherford, a former student of Thomson’s, tested the plum-pudding model.

• A narrow beam of alpha particles was directed at a very thin sheet of gold

Page 25: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Rutherford’s Gold Foil Experiment

• Most alpha particles went straight through, or were slightly deflected.

• A small fraction of the alpha particles bounced off the gold foil at very large angles.

Page 26: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Rutherford’s Atomic ModelThe Nuclear Atom

• Rutherford suggested a new theory of the atom based on the experimental results.– The atom is mostly empty space.– All the positive charge and amost all of the mass are

concentrated in a small positively charged region (nucleus)

– Protons & neutrons are in the positively charged nucleus

– Electrons are distributed around the nucleus and occupy almost all the volume of the atom.

Page 27: Do Now: Solve the following using the correct number of significant figures. 1)7.76 m + 2.1 m = 2)5.750 cg - 1.1 cg = 3)5555 kg + 444 kg = 4)1.23 m x 3.2.

Rutherford’s Atomic ModelThe Nuclear Atom

If an atom were the size of a football stadium, the nucleus would be the size of a marble.