Subatomic Particles, Average Atomic Mass, and Atomic Theory

In a stable atom the amount of electrons is equal to

• neutrons

• protons

• atomic mass

• neutrons + protons

What types of particles are found in the cloud surrounding the atom's nucleus?

• Positively charged particles and negatively charged particles
• Negatively charged particles only
• Neutral particles and positively charged particles
• Positively charged particles only

Tags

NGSS.MS-PS1-1

An atom with 19 protons, and 19 electrons and a mass of 39 has how many neutrons?

• 19
• 39
• 20
• 58

Tags

NGSS.MS-PS1-1

Where is the proton located?

• In the very dense nucleus
• Floating around in the negative electron cloud
• the loose nucleus
• the positive electron cloud

Tags

NGSS.MS-PS1-1

In an atom, electrons move in definite orbits around the nucleus.

• Thomson
• Rutherford
• Bohr
• Democritus

What scientist is best known for his "Plum Pudding" model of the atom?

• J.J. Thomson
• Ernest Rutherford
• John Dalton
• Democritus

Tags

NGSS.MS-PS1-1

Rutherford's gold foil experiment provided evidence that...

• negative and positive charges are spread evenly throughout the atom.
• alpha particles have a positive charge.
• gold is not a dense as previously thought.
• there is a dense positively charged nucleus at the center of an atom.

Tags

NGSS.MS-PS1-1

Who came up with the model of an atom pictured?

• J.J. Thompson
• Ernest Rutherford
• Neils Bohr
• James Chadwick

Tags

NGSS.MS-PS1-1

Who discovered the nucleus using the gold foil experiment?

• Democritus
• Robert Millikan
• James Chadwick
• Ernest Rutherford

He discovered the electron using cathode ray tube experiment.

• Joseph Thomson
• John Dalton
• Ernest Rutherford
• Robert Millikan