ERHS Chem Chapter 2 - The Atom

The majority of an atom's mass exists where?

• In the nucleus
• In the electron cloud
• In the space between the nucleus and the electrons
• In the neutrons

Which model of the atom shown in the picture was created after the discovery of electrons? This model proposed electrons floated freely in a positive sphere.

• JJ Thomson's Plum Pudding Model

• Rutherford's Nucleus Model

• Dalton's Model

• Bohr's Model

Which scientist is credited with the discovery of the electron?

• Bohr

• Rutherford

• Dalton

• Thomson

What is the mass number of an element with 40 protons, 40 electrons, and 46 neutrons? (Enter your answer as a number only)

How many electrons does an atom of potassium have according to the Periodic Table?

• 19

• 20

• 18

• 39

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NGSS.HS-PS1-1

How many neutrons does Uranium-238 have?

• 92
• 146
• 238
• 149

Which name best identifies an atom that has 16 protons, 19 neutrons, and 16 electrons?

• Sulfur

• Sulfur - 35

• Sulfur - 19

• Sulfur - 32

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NGSS.MS-PS1-1

Who proposed that atoms were tiny spheres in shape that could not be broken down into smaller pieces.

• Dalton

• J.J. Thompson

• Rutherford

• Lavoisier

In the gold foil experiment, most of the positively charged alpha particles passed through the gold foil, but some were deflected or bounced back.  What did we conclude because of this?  

• Atoms are small indivisible spheres
• Atoms are mostly empty space with a small, dense, positive center
• Atoms have negatively charged particles are found throughout the atom.

• Light is a wave, not a particle

Which two particles make up the nucleus of an atom?

• Protons and Electrons
• Protons and Neutrons
• Molecules and Compounds
• Neutrons and Electrons

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NGSS.HS-PS1-8