Choose the best answer.

1		The basic idea of the Rutherford atomic model is that the positive charge in an atom is ___________________.
			A)	spread uniformly throughout its volume
			B)	concentrated at its center
			C)	readily deflected by an incoming alpha particle
			D)	the same for all atoms
2		Nearly all the volume occupied by matter consists of __________________.
			A)	electrons
			B)	protons
			C)	neutrons
			D)	nothing
3		The atomic number of an element is the number of _________________.
			A)	protons in its nucleus
			B)	neutrons in its nucleus
			C)	electrons in its nucleus
			D)	protons and neutrons in its nucleus
4		The mass number of a nucleus is the number of ________________.
			A)	protons in the nucleus
			B)	neutrons in the nucleus
			C)	protons and neutrons in the nucleus
			D)	quarks in the nucleus
5		The nuclei of the isotopes of an element all contain the same number of __________________.
			A)	neutrons
			B)	protons
			C)	nucleons
			D)	electrons
6		One atomic mass unit is approximately equal to the mass of a(n) ____________________.
			A)	electron
			B)	atom of hydrogen
			C)	alpha particle
			D)	Neutrino
7		An electron is emitted by an atomic nucleus in the process of ____________________.
			A)	alpha decay
			B)	beta decay
			C)	gamma decay
			D)	nuclear fission
8		Gamma rays have the same basic nature as _______________.
			A)	alpha particles
			B)	beta particles
			C)	x-rays
			D)	sound waves
9		Which of these types of radiation has the greatest ability to penetrate matter?
			A)	alpha particles
			B)	beta particles
			C)	gamma rays
			D)	x-rays
10		Relative to the sum of the masses of its constituent particles, the mass of an atom is __________________.
			A)	greater
			B)	the same
			C)	smaller
			D)	any of the above, depending on the element
11		The binding energy per nucleon is ________________.
			A)	the same for all nuclei
			B)	greater for very small nuclei
			C)	greatest for nuclei of intermediate size
			D)	greatest for very large nuclei
12		In a chain reaction ___________________.
			A)	protons and neutrons join to form atomic nuclei
			B)	light nuclei join to form heavy ones
			C)	neutrons emitted during the fission of heavy nuclei induce fusions in other nuclei
			D)	uranium is burned in a type of furnace called a reactor
13		Enriched uranium is a better fuel for nuclear reactors than natural uranium because enriched uranium has a greater proportion of ___________________.
			A)	slow neutrons
			B)	deuterium
			C)	plutonium
			D)	235U
14		Of the following particles, the one that is not an elementary particle is the ____________________.
			A)	alpha particle
			B)	beta particle
			C)	neutron
			D)	neutrino
15		An example of a particle-antiparticle pair is the ___________________.
			A)	proton and positron
			B)	proton and neutron
			C)	neutron and neutrino
			D)	electron and positron
16		The mass of the neutrino is _________________.
			A)	equal to that of the neutron
			B)	equal to that of the electron
			C)	equal to that of a quark
			D)	very small or zero
17		Quarks are particles that __________________.
			A)	have no mass
			B)	have charges of lass than e
			C)	decay into protons
			D)	decay into neutrinos
18		A particle that is believed to consist of quarks is the ___________________.
			A)	electron
			B)	positron
			C)	neutron
			D)	neutrino
19		When a bromine isotope 3580Br decays into the krypton isotope 3680Kr, it emits ________________.
			A)	a gamma ray
			B)	an electron
			C)	a positron
			D)	an alpha particle
20		The half-life of tritium is 12.5 years. If we start out with 1 g of tritium, after 25 years there will be _________________.
			A)	no tritium left
			B)	¼ g of tritium left
			C)	½ g of tritium left
			D)	a total of 4 g of tritium