PS Chapter 9 Test Review

A scanning tunnel microscope (STM) allows scientists to see _____________.

• atoms

• quarks

• electrons

• none of the above

Which pair of individuals had the most similar ideas about matter?

• Dalton and Aristotle

• Democritus and Dalton

• Aristotle and Democritus

• Aristotle and Bohr

Two atoms that have different numbers of protons are _____________.

• different ions

• different isotopes

• different elements

• same ions

James Chadwick discovered _________________.

• protons

• neutrons

• electrons

• all of the above

Isotopes are atoms that have different __________________.

• mass numbers

• element names

• atomic numbers

• element symbols

A neutral atom would become an ion that has a charge of 2+ by __________.

• losing two protons

• losing two neutrons

• losing two electrons

• losing three electrons

Although carbon’s three isotopes are carbon-12, carbon-13, and carbon-14, its average atomic mass is 12.01 because ______________.

• carbon-12 is the heaviest isotope

• carbon-12 is most useful to humans

• carbon-12 is the most common isotope

• carbon-12 just looked the best

Which scientist discovered electrons?

• Dalton

• Aristotle

• Thomson

• Chadwick

Ernest Rutherford and his students did experiments that showed the existence of the __________.

• nucleus

• electron

• quark

• proton

Bohr proposed that electrons are located in __________.

• the nucleus

• an electron cloud

• circular orbits around the nucleus

• there are no electrons in an atom