CHM 2045 EXAM 1
(1) The mass number is equal to...
A) the sum of the number of the neutrons and electrons.
B) the sum of the number of the electrons and protons.
C) the sum of the number of protons and neutrons.
D) the sum of the number of protons, neutrons, and electrons. - ------------ANSWER:
C) the sum of the number of protons and neutrons
(1) Which of the following represent isotopes?
A:25 B:21 C:27 D: 25
21 25 21 23
A) A and D B) A and B C) C and D
D) A and C - ------------ANSWER: D) A and C
(1) Which of the following statements about subatomic particles is TRUE?
A) Protons have about the same mass as electrons.
B) Neutrons and electrons are found in the nucleus of an atom.
C) Protons and neutrons have opposite, but equal in magnitude, charges.
D) A neutral atom contains the same number of protons and electrons.
E) Electrons make up most of the mass of an atom. - ------------ANSWER: D) A
neutral atom contains the same number of protons and electrons.
(2) An iron-56 nucleus contains
A) 56 protons and 56 neutrons.
B) 26 protons and 30 neutrons.
C) 56 protons and 26 neutrons.
D) 30 protons and 26 neutrons.
E) 26 protons and 26 neutrons. - ------------ANSWER: B) 26 protons and 30 neutrons
(2) Identify the description of an atom.
A) electrons in nucleus; protons and neutrons in orbitals
B) protons and neutrons in nucleus; electrons in orbitals
C) neutrons in nucleus; protons and electrons in orbitals
D) protons and electrons in nucleus; neutrons in orbitals
E) neutrons and electrons in nucleus; protons in orbitals - ------------ANSWER: B)
protons and neutrons in nucleus; electrons in orbitals
, (5) The atomic number indicates __________.
A) the total number of neutrons and protons in a nucleus
B) the number of neutrons in a nucleus
C) the number of protons or electrons in a neutral atom
D) the number of atoms in 1 g of an element
E) the number of different isotopes of an element - ------------ANSWER: C) the
number of protons or electrons in a neutral atom
(6) What is the identity of element Q if the ion Q
2+
contains 10 electrons?
A) Ne B) O
C) Mg
D) C - ------------ANSWER: C) Mg
A 30.0 g sample of an element contains 3.47X 10^23
atoms. Identify the element.
A) Cr B) O C) Mg D) Fe - ------------ANSWER: A) Cr
A hypothetical element, E, has only two naturally occurring isotopes: E-46 with a
mass of 46.046
amu and a natural abundance of 64.08%, and E-51 with a mass of 50.826 amu.
What is the atomic mass
of element E?
A) 48.50 amu
B) 47.76 amu
C) 49.11 amu D) 47.44 amu E) 48.44 amu - ------------ANSWER: B) 47.76 amu
A hypothetical element, E, has two naturally occuring isotopes:
E-38 38.012 amu 75.68%
E-46 45.981 amu 24.32%
The element's atomic mass would be closest to which of the elements?
A) K B) Ca
C) Cl D) Sc
E) Ar - ------------ANSWER: E) Ar
Calculate the atomic mass of silver if silver has 2 naturally occurring isotopes with
the following
masses and natural abundances:
Ag-107 106.90509 amu 51.84%
Ag-109 108.90476 amu 48.46%
A) 107.79 amu B) 108.32 amu
(1) The mass number is equal to...
A) the sum of the number of the neutrons and electrons.
B) the sum of the number of the electrons and protons.
C) the sum of the number of protons and neutrons.
D) the sum of the number of protons, neutrons, and electrons. - ------------ANSWER:
C) the sum of the number of protons and neutrons
(1) Which of the following represent isotopes?
A:25 B:21 C:27 D: 25
21 25 21 23
A) A and D B) A and B C) C and D
D) A and C - ------------ANSWER: D) A and C
(1) Which of the following statements about subatomic particles is TRUE?
A) Protons have about the same mass as electrons.
B) Neutrons and electrons are found in the nucleus of an atom.
C) Protons and neutrons have opposite, but equal in magnitude, charges.
D) A neutral atom contains the same number of protons and electrons.
E) Electrons make up most of the mass of an atom. - ------------ANSWER: D) A
neutral atom contains the same number of protons and electrons.
(2) An iron-56 nucleus contains
A) 56 protons and 56 neutrons.
B) 26 protons and 30 neutrons.
C) 56 protons and 26 neutrons.
D) 30 protons and 26 neutrons.
E) 26 protons and 26 neutrons. - ------------ANSWER: B) 26 protons and 30 neutrons
(2) Identify the description of an atom.
A) electrons in nucleus; protons and neutrons in orbitals
B) protons and neutrons in nucleus; electrons in orbitals
C) neutrons in nucleus; protons and electrons in orbitals
D) protons and electrons in nucleus; neutrons in orbitals
E) neutrons and electrons in nucleus; protons in orbitals - ------------ANSWER: B)
protons and neutrons in nucleus; electrons in orbitals
, (5) The atomic number indicates __________.
A) the total number of neutrons and protons in a nucleus
B) the number of neutrons in a nucleus
C) the number of protons or electrons in a neutral atom
D) the number of atoms in 1 g of an element
E) the number of different isotopes of an element - ------------ANSWER: C) the
number of protons or electrons in a neutral atom
(6) What is the identity of element Q if the ion Q
2+
contains 10 electrons?
A) Ne B) O
C) Mg
D) C - ------------ANSWER: C) Mg
A 30.0 g sample of an element contains 3.47X 10^23
atoms. Identify the element.
A) Cr B) O C) Mg D) Fe - ------------ANSWER: A) Cr
A hypothetical element, E, has only two naturally occurring isotopes: E-46 with a
mass of 46.046
amu and a natural abundance of 64.08%, and E-51 with a mass of 50.826 amu.
What is the atomic mass
of element E?
A) 48.50 amu
B) 47.76 amu
C) 49.11 amu D) 47.44 amu E) 48.44 amu - ------------ANSWER: B) 47.76 amu
A hypothetical element, E, has two naturally occuring isotopes:
E-38 38.012 amu 75.68%
E-46 45.981 amu 24.32%
The element's atomic mass would be closest to which of the elements?
A) K B) Ca
C) Cl D) Sc
E) Ar - ------------ANSWER: E) Ar
Calculate the atomic mass of silver if silver has 2 naturally occurring isotopes with
the following
masses and natural abundances:
Ag-107 106.90509 amu 51.84%
Ag-109 108.90476 amu 48.46%
A) 107.79 amu B) 108.32 amu
