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WorksheetsChapter 3-Revision
Total questions: 22
Worksheet time: 11mins
The atomic number of an element is
the mass of the element.
1 mol of the element.
the number of protons in each atom of the element.
the number of neutrons in each atom of the element.
Hydrogen that is composed of atoms with two neutrons is called
protium.
deuterium.
tritium.
helium.
Isotopes are atoms of the same element that have different
masses.
charges.
numbers of electrons.
atomic numbers.
Mass number is
the average atomic mass of an element.
the total number of electrons in an atom of an element.
the total number of protons in an atom of an element.
the total number of protons and neutrons in an atom of an element.
The isotope uranium-235 has 92 protons and 143 neutrons. Therefore, its mass number is
92.
235.
143.
impossible to determine.
To take a weighted average of all the naturally occurring isotopes of an element in order to arrive at an average atomic mass, you would
a. multiply the mass of each isotope by the decimal fraction representing its abundance naturally, then add all these products together.
b. use the isotope with the largest mass.
c. use the isotope with the most average mass.
d. add all the masses of all of the isotopes, then divide by the number of isotopes.
One mole is defined as
a. the volume of a substance with a mass of 12 g.
b. the amount of a substance that contains as many particles as there are atoms in exactly 12 g of carbon-12.
c. the amount of a substance that contains as many particles as there are atoms in exactly 12 g of silver.
d. an amount of a substance that contains enough atoms to have a mass of 12 g.
The molar mass of an element is numerically equal to the element’s
a. average number of electrons.
b. average number of protons.
c. average atomic mass.
d. average atomic number.
John Dalton thought that atoms
a. contain molecules.
b. cannot be broken down further.
c. are all composed of carbon.
d. have no mass.
Using improved chemistry equipment in the late 1700s, chemists observed that mass is neither created nor destroyed in a chemical reaction. This scientific law is called the law of
a. definite proportions.
b. gravity.
c. conservation of mass.
d. conservation of momentum.
The fact that every sample of a particular chemical compound contains the same elements in exactly the same proportions by mass is known as the law of
a. conservation of energy.
b. conservation of mass.
c. atomic theory.
d. definite proportions.
If two or more compounds are composed of the same two elements, then the ratio of the masses of the second element that is combined with a certain mass of the first element is always a ratio of small whole numbers. This statement is called the law of
a. definite proportions.
b. conservation of mass.
c. atomic theory.
d. multiple proportions.
Experiments with cathode rays being deflected by a magnetic field show that cathode rays are composed of particles that are
a. magnetic.
b. negatively charged.
c. positively charged.
d. neutral in charge.
Cathode rays are composed of particles that are now known as
a. positrons.
b. neutrons.
c. protons.
d. electrons.
In 1911, Ernest Rutherford conducted his now famous goldfoil experiment. During the experiment, alpha particles bombarded a thin piece of gold foil. The alpha particles were expected to pass easily through the gold foil. Every now and then, however, an alpha particle bounced back—an unexpected result. Rutherford concluded that these particles were striking
a. a tiny region of positive charge.
b. a dense region of negative charge.
c. a dense region of neutrons.
d. a tiny region with a strong magnetic field
Rutherford called the region that deflected alpha particles
a. an electron.
b. a positron.
c. a nucleus.
d. a quark.
The total volume of the nucleus of an atom is
a. very large compared with the rest of the atom.
b. very small compared with the rest of the atom.
c. about the same size as an electron.
d. smaller than a neutron.
Electrons can be found
a. inside protons.
b. inside neutrons.
c. attached to the nucleus.
d. moving rapidly outside the nucleus.
Most of an atom is
a. dense.
b. fluid.
c. empty.
d. the nucleus.
What is the charge of a neutron?
a. positive
b. negative
c. neutral
d. None of the above
Which of the following states an important result of Rutherford’s gold-foil experiment?
Atoms have mass.
Electrons have a negative charge.
Neutrons are uncharged particles.
The atom is mostly empty space.
A student collected a total of 36.04 g of water from a reaction. What number of moles of water does this represent?
(the molar mass of water 18 g/mol)
0.05 mol
1.00 mol
1.50 mol
2.00 mol
