BS 161 EXAM 1 QUESTIONS | TESTED AND PROVEN
ANSWERS | LATEST UPDATE 2024/2025 100%
(GRADE A+)
Where do lipids, a class of organic compounds, fit on the hierarchy of biological organization?
Ans>> DNA
What are characteristics of an ionic bond?
Ans>> An electron is completely pulled from one atom to another. The electronegativity
difference is always high between atoms of this bond type.
What are characteristics of a covalent bond?
Ans>> Atoms of this bond might have equal electronegativities. This bond may also be polar or
nonpolar.
What are the 4 most common elements in living organisms?
Ans>> Carbon, Oxygen, Hydrogen and Nitrogen
What elements are present in trace amounts only?
1
,Ans>> Iodine and Zinc
What elements are found in greater than trace amounts?
Ans>> Sodium, Chloride, Calcium, phosphorus, potassium, sulfur, magnesium and iron
The atomic number of carbon-13 is ____
Ans>> 6
The atomic mass of carbon-13 is ______
Ans>> 13
C-12, C-13, and C-14 have the same number of protons but different numbers of neutrons so
they are ______.
Ans>> Isotopes
Atoms have gained or lost electrons and are no longer electrically neutral are called _____.
Ans>> Ions
2
,Describe a single covalent bond.
Ans>> Holds a molecule of hydrogen together, involves 2 atoms sharing 2 electrons and two
chlorine atoms are held together by this bond.
Describe an Ionic bond.
Ans>> Formed by an attraction between atoms with opposite charges, bond that hold NaCl
together, Involves a transfer of one or more electrons from one atom to another, Leads to the
formation of a crystal lattice rather than distinct molecules and Weakest type of bond shown.
Describe a double covalent bond.
Ans>> hold a molecule of oxygen together, Involves 2 atoms sharing 4 electrons, strongest type
of bond shown and carbon dioxide is held together by this type of bond.
T/F
A water molecule is held together by 2 single polar covalent bond
Ans>> TRUE
3
, T/F
Because oxygen has a greater electronegativity than hydrogen, water molecules are polar w/ 2
partial negative charges near the oxygen atom and one partial positive charge near each
hydrogen atom.
Ans>> TRUE
T/F
Atoms differ in their affinity for neutrons, a property called electronegativity.
Ans>> FALSE
T/F
In general, electronegativity increases from left to right across each row of the periodic table and
also increases down each column.
Ans>> FALSE
T/F
In a nonpolar covalent bond there is an equal sharing of electrons between two atoms while polar
covalent bonds involve an unequal sharing of electrons.
4
ANSWERS | LATEST UPDATE 2024/2025 100%
(GRADE A+)
Where do lipids, a class of organic compounds, fit on the hierarchy of biological organization?
Ans>> DNA
What are characteristics of an ionic bond?
Ans>> An electron is completely pulled from one atom to another. The electronegativity
difference is always high between atoms of this bond type.
What are characteristics of a covalent bond?
Ans>> Atoms of this bond might have equal electronegativities. This bond may also be polar or
nonpolar.
What are the 4 most common elements in living organisms?
Ans>> Carbon, Oxygen, Hydrogen and Nitrogen
What elements are present in trace amounts only?
1
,Ans>> Iodine and Zinc
What elements are found in greater than trace amounts?
Ans>> Sodium, Chloride, Calcium, phosphorus, potassium, sulfur, magnesium and iron
The atomic number of carbon-13 is ____
Ans>> 6
The atomic mass of carbon-13 is ______
Ans>> 13
C-12, C-13, and C-14 have the same number of protons but different numbers of neutrons so
they are ______.
Ans>> Isotopes
Atoms have gained or lost electrons and are no longer electrically neutral are called _____.
Ans>> Ions
2
,Describe a single covalent bond.
Ans>> Holds a molecule of hydrogen together, involves 2 atoms sharing 2 electrons and two
chlorine atoms are held together by this bond.
Describe an Ionic bond.
Ans>> Formed by an attraction between atoms with opposite charges, bond that hold NaCl
together, Involves a transfer of one or more electrons from one atom to another, Leads to the
formation of a crystal lattice rather than distinct molecules and Weakest type of bond shown.
Describe a double covalent bond.
Ans>> hold a molecule of oxygen together, Involves 2 atoms sharing 4 electrons, strongest type
of bond shown and carbon dioxide is held together by this type of bond.
T/F
A water molecule is held together by 2 single polar covalent bond
Ans>> TRUE
3
, T/F
Because oxygen has a greater electronegativity than hydrogen, water molecules are polar w/ 2
partial negative charges near the oxygen atom and one partial positive charge near each
hydrogen atom.
Ans>> TRUE
T/F
Atoms differ in their affinity for neutrons, a property called electronegativity.
Ans>> FALSE
T/F
In general, electronegativity increases from left to right across each row of the periodic table and
also increases down each column.
Ans>> FALSE
T/F
In a nonpolar covalent bond there is an equal sharing of electrons between two atoms while polar
covalent bonds involve an unequal sharing of electrons.
4
