Atomic Theory and Structure

Value representing the number of protons in an element

• Atomic Mass

• Mass Number

• Valence Electrons

• Atomic Number

The smallest particle of an element that shows all the properties of that element.

• Subatomic Particles

• Atom

• Quarks

• Gluons

Where electrons are likely to be found as they travel around the nucleus

• Nucleus

• Electron Cloud

• Within a Proton

• Within a Neutron

A tiny but very dense, positively charged portion of the atom that holds most of the atomic mass

• Electron Shells

• Orbitals

• Electron Cloud

• Nucleus

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How many protons, neutrons, and electrons does sulfur have? It's atomic number is 16 and it's atomic mass is 32.

• 16 protons, 16 neutrons, and 16 electrons

• 16 protons, 32 neutrons, and 16 electrons

• 16 protons, 16 neutrons, and 32 electrons

• 32 protons, 16 neutrons, and 16 electrons.

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How many protons does chlorine have?

• 35

• 36

• 17

• 18

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Silicon has a mass number of 28 and an atomic number of 14. How many protons does it have?

• 28

• 14

• 42

• 7

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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

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.