Chapter 4. Section 2 & 3

What can you conclude from the deflection of a cathode ray in a magnetic field?

• The ray must be composed of charged particles.

• The ray must be composed of iron.

• The ray must have a positive charge.

• The ray must need to travel in a vacuum

Which of the following particles has a mass that is almost the same as the mass of a proton?

• neutron

• electron

• positron

• beta particle

Which scientist determined that almost all of an atom's mass of is located in its nucleus?

• Dalton

• Democritus

• Rutherford

• Thomson

In the plum pudding model of the atom, where is most of the mass of the atom?

• in the electrons

• in the matter between the electrons

• in the nucleus

• in the protons

Why are all atomic masses not nearly whole numbers?

• This is due to the mass of all the electrons in the atom

• This is because of experimental error.

• This is because atomic masses are the weighted average of the masses of all naturally-occurring isotopes.

• This is because atomic masses are the weighted average of the masses of all naturally-occurring isotopes.

The atomic number of an element is defined by its number of ________.

• protons

• neutrons

• electrons

• nuclei

The sum of the protons and neutrons in a nucleus is __________

• The atomic number

• The mass number

• Avogadro´s number

• The element number

Which of the following is true for any atom?

• atomic number = number of protons = number of electrons

• atomic number = number of neutrons = number of electrons

• mass number = number of protons = number of electrons

• mass number = number of protons = number of neutrons

How is the atomic mass unit (amu) defined?

• 1/12 the mass of a carbon-12 atom

• 1/14 the mass of a nitrogen-14 atom

• 1/13 the mass of a carbon-13 atom

• 1/16 the mass of an oxygen-16 atom

Why were Democritus's ideas not science?

• They were not supported by experiment.

• They were partly incorrect.

• They went against the ideas of more influential philosophers.

• They went against the ideas of more influential philosophers.