Chemistry Chapter 4 (Due October 31) [Test October 31]
Matching
Match each item with the correct statement below.
a. proton
d. electron
b. nucleus
e. neutron
c. atom
____
____
____
____
____
1.
2.
3.
4.
5.
the smallest particle of an element that retains the properties of that element
a positively charged subatomic particle
a negatively charged subatomic particle
a subatomic particle with no charge
the central part of an atom, containing protons and neutrons
Match each item with the correct statement below.
a. mass number
d. atomic mass
b. atomic mass unit
e. isotope
c. atomic number
____ 6.
____ 7.
____ 8.
____ 9.
____ 10.
atoms with the same number of protons, but different numbers of neutrons in the nucleus of an atom
the total number of protons and neutrons in the nucleus of an atom
the number of protons in the nucleus of an element
the weighted average of the masses of the isotopes of an element
one-twelfth the mass of a carbon atom having six protons and six neutrons
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 11. Who was the man who lived from 460B.C.–370B.C. and was among the first to suggest the idea of atoms?
a. Atomos
c. Democritus
b. Dalton
d. Thomson
____ 12. Dalton's atomic theory included which idea?
a. All atoms of all elements are the same size.
b. Atoms of different elements always combine in one-to-one ratios.
c. Atoms of the same element are always identical.
d. Individual atoms can be seen with a microscope.
____ 13. The comparison of the number of atoms in a copper coin the size of a penny with the number of people on
Earth is made to illustrate which of the following?
a. that atoms are indivisible
b. that atoms are very small
c. that atoms are very large
d. that in a copper penny, there is one atom for every person on Earth
____ 14. The range in size of most atomic radii is approximately ____.
a. 2 to 5 cm
c. 5 10 m to 2 10 m
b. 2 to 5 nm
d. 5 10 m to 2 10 m
____ 15. Dalton hypothesized that atoms are indivisible and that all atoms of an element are identical. It is now known
that ____.
a. all of Dalton's hypotheses are correct
b. atoms of an element can have different numbers of protons
c. atoms are divisible
d. all atoms of an element are not identical but they must all have the same mass
____ 16. Why did J. J. Thomson reason that electrons must be a part of the atoms of all elements?
a. Cathode rays are negatively-charged particles.
b. Cathode rays can be deflected by magnets.
c. An electron is 2000 times lighter than a hydrogen atom.
d. Charge-to-mass ratio of electrons was the same, regardless of the gas used.
____ 17. Which of the following is true about subatomic particles?
a. Electrons are negatively charged and are the heaviest subatomic particle.
b. Protons are positively charged and the lightest subatomic particle.
c. Neutrons have no charge and are the lightest subatomic particle.
d. The mass of a neutron nearly equals the mass of a proton.
____ 18. Who conducted experiments to determine the quantity of charge carried by an electron?
a. Rutherford
c. Dalton
b. Millikan
d. Thomson
____ 19. Which hypothesis led to the discovery of the proton?
a. When a neutral hydrogen atom loses an electron, a positively-charged particle should
remain.
b. A proton should be 1840 times heavier than an electron.
c. Cathode rays should be attracted to a positively-charged plate.
d. The nucleus of an atom should contain neutrons.
____ 20. Which of the following is correct concerning subatomic particles?
a. The electron was discovered by Goldstein in 1886.
b. The neutron was discovered by Chadwick in 1932.
c. The proton was discovered by Thomson in 1880.
d. Cathode rays were found to be made of protons.
____ 21. All atoms are ____.
a. positively charged, with the number of protons exceeding the number of electrons
b. negatively charged, with the number of electrons exceeding the number of protons
c. neutral, with the number of protons equaling the number of electrons
d. neutral, with the number of protons equaling the number of electrons, which is equal to the
number of neutrons
____ 22. As a consequence of the discovery of the nucleus by Rutherford, which model of the atom is thought to be
true?
a. Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.
b. The nucleus is made of protons, electrons, and neutrons.
c. Electrons are distributed around the nucleus and occupy almost all the volume of the atom.
d. The nucleus is made of electrons and protons.
____ 23. The atomic number of an element is the total number of which particles in the nucleus?
a. neutrons
c. electrons
b. protons
d. protons and electrons
____ 24. What does the number 84 in the name krypton-84 represent?
a. the atomic number
c. the sum of the protons and electrons
b. the mass number
d. twice the number of protons
____ 25. Isotopes of the same element have different ____.
a. positions on the periodic table
c. atomic numbers
b. chemical behavior
d. mass numbers
____ 26. Using the periodic table, determine the number of neutrons in O.
a. 4
c. 16
b. 8
d. 24
____ 27. How many protons, electrons, and neutrons does an atom with atomic number 50 and mass number 125
contain?
a. 50 protons, 50 electrons, 75 neutrons
c. 120 neutrons, 50 protons, 75 electrons
b. 75 electrons, 50 protons, 50 neutrons
d. 70 neutrons, 75 protons, 50 electrons
____ 28. Which of the following statements is NOT true?
a. Atoms of the same element can have different masses.
b. Atoms of isotopes of an element have different numbers of protons.
c. The nucleus of an atom has a positive charge.
d. Atoms are mostly empty space.
____ 29. If E is the symbol for an element, which two of the following symbols represent isotopes of the same
element?
1. E
2. E
3. E
4. E
a. 1 and 2
c. 1 and 4
b. 3 and 4
d. 2 and 3
____ 30. Select the correct symbol for an atom of tritium.
a. n
c. H
b. H
d. H
____ 31. Which of the following sets of symbols represents isotopes of the same element?
a.
c.
J
J
J
M
M
M
b.
d.
L
L
L
Q
Q
Q
____ 32. How is the number of neutrons in the nucleus of an atom calculated?
a. Add the number of electrons and protons together.
b. Subtract the number of electrons from the number of protons.
c. Subtract the number of protons from the mass number.
d. Add the mass number to the number of electrons.
____ 33. In which of the following is the number of neutrons correctly represented?
a.
c.
F has 0 neutrons.
Mg has 24 neutrons.
b.
d.
As has 108 neutrons.
U has 146 neutrons.
____ 34. How do the isotopes hydrogen-1 and hydrogen-2 differ?
a. Hydrogen-2 has one more electron than hydrogen-1.
b. Hydrogen-2 has one neutron; hydrogen-1 has none.
c. Hydrogen-2 has two protons; hydrogen-1 has one.
d. Hydrogen-2 has one proton; hydrogen-1 has none.
____ 35. Which of the following isotopes has the same number of neutrons as phosphorus-31?
a.
c.
P
Si
b.
d.
S
Si
____ 36. Which of the following equals one atomic mass unit?
a. the mass of one electron
b. the mass of one helium-4 atom
c. the mass of one carbon-12 atom
d. one-twelfth the mass of one carbon-12 atom
____ 37. Which of the following statements is NOT true?
a. Protons have a positive charge.
b. Electrons are negatively charged and have a mass of 1 amu.
c. The nucleus of an atom is positively charged.
d. Neutrons are located in the nucleus of an atom.
____ 38. Why do chemists use relative masses of atoms compared to a reference isotope rather than the actual masses
of the atoms?
a. The actual mass of an electron is very large compared to the actual mass of a proton.
b. The actual masses of atoms are very small and difficult to work with.
c. The number of subatomic particles in atoms of different elements varies.
d. The actual masses of protons, electrons, and neutrons are not known.
____ 39. The atomic mass of an element depends upon the ____.
a. mass of each electron in that element
b. mass of each isotope of that element
c. relative abundance of protons in that element
d. mass and relative abundance of each isotope of that element
____ 40. Which of the following is necessary to calculate the atomic mass of an element?
a. the atomic mass of carbon-12
b. the atomic number of the element
c. the relative masses of the element’s protons and neutrons
d. the masses of each isotope of the element
Short Answer
41. List the number of protons, neutrons, and electrons in
C.
42. Chlorine has two naturally occurring isotopes, Cl-35 and Cl-37. The atomic mass of chlorine is 35.45. Which
of these two isotopes of chlorine is more abundant?
43. Consider an element Z that has two naturally occurring isotopes with the following percent abundances: the
isotope with a mass number of 19.0 is 55.0% abundant; the isotope with a mass number of 21.0 is 45.0%
abundant. What is the average atomic mass for element Z?
44. A fictitious element X is composed of 10.0 percent of the isotope
, 20.0 percent of the isotope
70.0 percent of the isotope
. Estimate the atomic mass of element X.
, and
45. The element chromium has four naturally occurring isotopes. Use the relative abundance of each to calculate
the average atomic mass of chromium.
Cr = 4.34%,
Cr = 83.79%,
Cr = 9.50%,
Numeric Response
46. What is the relative charge of a proton?
Cr = 2.37%.
47. Use the periodic table to determine the number of electrons in a neutral atom of lithium.
48. How many protons are present in an atom of Be-9?
49. What is the total number of subatomic particles in the nucleus of an atom of
Bi?
50. Determine the number of electrons in an atom of iridium.
51. What is the atomic number for an element with 41 neutrons and a mass number of 80?
52. How many electrons are in an atom of gold?
53. Use the periodic table to determine the number of neutrons in nitrogen-14.
54. How many neutrons are present in an atom of the isotope
55. Calculate the number of neutrons in
Pb.
U?