Unit 2 Review

J.J. Thomson provided evidence that an atom...

• is the smallest particle of matter
• contains negatively charged particles
• has an overall negative charge
• has an overall positive charge

Rutherford discovered the...

• electron
• proton
• neutron
• nucleus

Isotopes are elements with a different amount of

• protons
• neutrons
• electrons
• atoms

an element will always have the same number of 

• neutrons
• protons
• isotopes
• atoms

Which particle does not contribute mass to the atom?

• Proton
• Neutron
• Electron
• Nucleus

What scientist is best known for his gold foil experiment?

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

An atom has 10 protons and a mass of 18. It has __ neutrons

• 10
• 18
• 28
• 8

An ______________ is the same element, with the same number of protons, but different numbers of neutrons

• Atom
• Isotope
• Atomic Number
• Mass Number

The smallest particle into which an element can be divided and still be the same substance

• neutron
• atom
• electron

How many neutrons does uranium-239 have

• 92
• 147
• 239
• 331