1
BSC2010 Exam 1 Questions with Answers
(100% Correct Answers)
A substance that cannot be broken down into other substances by ordinary
chemical procedures is a(n) _____. Answer: element
About 25 of the 92 natural elements are known to be essential to life. Which 4
of these 25 elements make up approximately 96% of living matter? Answer:
carbon, hydrogen, nitrogen, oxygen
Given what you know about the human body, what do you think accounts for
the high percentage of oxygen (65.0%)? Answer: The human body is mostly
made up of water (H2O), and there is one oxygen atom in each molecule of
water. Note that, although each water molecule also contains two hydrogen
atoms, the atomic mass of hydrogen (about 1) is much smaller than the atomic
mass of oxygen (about 16). Because of this, hydrogen contributes less to human
body mass than oxygen.
The innermost electron shell of an atom can hold up to _____ electrons.
Answer: 2
Which of these relationships is true of an uncharged atom? Answer: The
number of protons is equal to the number of electrons.
What determines the types of chemical reactions that an atom participates in?
Answer: the number of electrons in the outermost electron shell
What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6
electrons? Answer: 6. Atomic number is the number of protons in an atom.
Which of these refers to atoms with the same atomic number but different
atomic masses? Answer: These atoms are isotopes.
Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons
does fluorine have? Answer: Atomic mass is equal to the number of protons
plus the number of neutrons (19-9 = 10)
,2
An uncharged atom of boron has an atomic number of 5 and an atomic mass of
11. How many protons does boron have? Answer: 5. The atomic number is
equal to the number of protons.
What is the mass number of an ion with 109 electrons, 158 neutrons, and a +1
charge? Answer: 268
Compare the three atom diagrams. Which one shows the electron with the
highest potential energy?
Diagram of an atomic nucleus with three electron shells. The first shell is
closest to the nucleus. The second shell is farther away from the nucleus than
the first shell. The third shell is farthest away from the nucleus. An electron is
shown in the first shell.
Diagram of an atomic nucleus with three electron shells. The first shell is
closest to the nucleus. The second shell is farther away from the nucleus than
the first shell. The third shell is farthest away from the nucleus. An electron is
shown in the third shell.
Diagram of an atomic nucleus with three electron shells. The first shell is
closest to the nucleus. The second shell is farther away from the nucleus than
the first shell. The third shell is farthest away from the nucleus. An electron is
shown in the second shell. Answer: The farther an electron shell is from the
nucleus, the more potential energy an electron has to gain in order to move into
it.
Electrons are held in an atom by attraction to what particle or location?
Answer: Attraction to the positively charged protons in the nucleus
What can happen to an electron when sunlight hits it? Answer: It can move out
to a higher electron shell. It can stay in its original shell.
Movement of electrons between shells requires input or release of discrete
amounts of energy. Answer: 1. When an electron absorbs the required amount
, 3
of light energy, it moves from a lowerelectron shell to a higher electron shell,
which is farther from the nucleus.
2. When an electron loses a discrete amount of energy, it moves from a higher
electron shell to a lower electron shell, which is closer to the nucleus.
Changing the number of _____ would change an atom into an atom of a
different element. Answer: protons in an atom. Atoms of each element have a
unique number of protons within their nuclei. Changing the number of protons
in an atom occurs only in nuclear reactions, not chemical reactions.
An ion with six protons, seven neutrons, and a charge of 2+ has an atomic
number of ________. Answer: 6
Carbon-14 has the same ________. Answer: number of protons but more
neutrons than carbon-12
Refer to the following figure (first three rows of the periodic table) to answer
the questions below.
First three rows of the periodic table, showing name of element, atomic
number, symbol, and electron diagram.
Which pair of elements would likely have similar valency and thus similar
chemical behavior? Answer: nitrogen and phosphorus
Refer to the following figure to answer the questions below.
Boxes from periodic table, showing atomic mass, symbol, and atomic number.
Mass 12, symbol C, number 6; Mass 16, symbol O, number 8; Mass 1, symbol
H, number 1; Mass 14, symbol N, number 7; Mass 32, symbol S, number 16;
Mass 31, symbol P, number 15
BSC2010 Exam 1 Questions with Answers
(100% Correct Answers)
A substance that cannot be broken down into other substances by ordinary
chemical procedures is a(n) _____. Answer: element
About 25 of the 92 natural elements are known to be essential to life. Which 4
of these 25 elements make up approximately 96% of living matter? Answer:
carbon, hydrogen, nitrogen, oxygen
Given what you know about the human body, what do you think accounts for
the high percentage of oxygen (65.0%)? Answer: The human body is mostly
made up of water (H2O), and there is one oxygen atom in each molecule of
water. Note that, although each water molecule also contains two hydrogen
atoms, the atomic mass of hydrogen (about 1) is much smaller than the atomic
mass of oxygen (about 16). Because of this, hydrogen contributes less to human
body mass than oxygen.
The innermost electron shell of an atom can hold up to _____ electrons.
Answer: 2
Which of these relationships is true of an uncharged atom? Answer: The
number of protons is equal to the number of electrons.
What determines the types of chemical reactions that an atom participates in?
Answer: the number of electrons in the outermost electron shell
What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6
electrons? Answer: 6. Atomic number is the number of protons in an atom.
Which of these refers to atoms with the same atomic number but different
atomic masses? Answer: These atoms are isotopes.
Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons
does fluorine have? Answer: Atomic mass is equal to the number of protons
plus the number of neutrons (19-9 = 10)
,2
An uncharged atom of boron has an atomic number of 5 and an atomic mass of
11. How many protons does boron have? Answer: 5. The atomic number is
equal to the number of protons.
What is the mass number of an ion with 109 electrons, 158 neutrons, and a +1
charge? Answer: 268
Compare the three atom diagrams. Which one shows the electron with the
highest potential energy?
Diagram of an atomic nucleus with three electron shells. The first shell is
closest to the nucleus. The second shell is farther away from the nucleus than
the first shell. The third shell is farthest away from the nucleus. An electron is
shown in the first shell.
Diagram of an atomic nucleus with three electron shells. The first shell is
closest to the nucleus. The second shell is farther away from the nucleus than
the first shell. The third shell is farthest away from the nucleus. An electron is
shown in the third shell.
Diagram of an atomic nucleus with three electron shells. The first shell is
closest to the nucleus. The second shell is farther away from the nucleus than
the first shell. The third shell is farthest away from the nucleus. An electron is
shown in the second shell. Answer: The farther an electron shell is from the
nucleus, the more potential energy an electron has to gain in order to move into
it.
Electrons are held in an atom by attraction to what particle or location?
Answer: Attraction to the positively charged protons in the nucleus
What can happen to an electron when sunlight hits it? Answer: It can move out
to a higher electron shell. It can stay in its original shell.
Movement of electrons between shells requires input or release of discrete
amounts of energy. Answer: 1. When an electron absorbs the required amount
, 3
of light energy, it moves from a lowerelectron shell to a higher electron shell,
which is farther from the nucleus.
2. When an electron loses a discrete amount of energy, it moves from a higher
electron shell to a lower electron shell, which is closer to the nucleus.
Changing the number of _____ would change an atom into an atom of a
different element. Answer: protons in an atom. Atoms of each element have a
unique number of protons within their nuclei. Changing the number of protons
in an atom occurs only in nuclear reactions, not chemical reactions.
An ion with six protons, seven neutrons, and a charge of 2+ has an atomic
number of ________. Answer: 6
Carbon-14 has the same ________. Answer: number of protons but more
neutrons than carbon-12
Refer to the following figure (first three rows of the periodic table) to answer
the questions below.
First three rows of the periodic table, showing name of element, atomic
number, symbol, and electron diagram.
Which pair of elements would likely have similar valency and thus similar
chemical behavior? Answer: nitrogen and phosphorus
Refer to the following figure to answer the questions below.
Boxes from periodic table, showing atomic mass, symbol, and atomic number.
Mass 12, symbol C, number 6; Mass 16, symbol O, number 8; Mass 1, symbol
H, number 1; Mass 14, symbol N, number 7; Mass 32, symbol S, number 16;
Mass 31, symbol P, number 15
