59 notecards = 15 pages (4 cards per page)
About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?
A) carbon, sodium, hydrogen, nitrogen
Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?
Which of the following statements is false?
What factors are most important in determining which elements are
most common in living matter?
Why is each element unique and different from other elements in
Knowing just the atomic mass of an element allows inferences about
which of the following?
In what way are elements in the same column of the periodic table the
Oxygen has an atomic number of 8 and a mass number of 16. Thus, what
is the atomic mass of an oxygen atom?
) The nucleus of a nitrogen atom contains 7 neutrons and 7 protons.
Which of the following is a correct statement concerning nitrogen?
Molybdenum has an atomic number of 42. Several common isotopes exist,
with mass numbers of 92, 94, 95, 96, 97, 98, and 100. Therefore, which
of the following can be true?
Carbon-12 is the most common isotope of carbon, and has an atomic
mass of 12 daltons. A mole of carbon in naturally occurring coal,
however, weighs slightly more than 12 grams. Why?
The precise weight of a mole of some pure elements like silicon (Si)
can vary slightly from the standard atomic mass, or even from sample
to sample. Why?
One difference between carbon-12 (12/6 C) is that carbon-14 (14/6 C)
An atom has 6 electrons in its outer shell. How many unpaired
electrons does it have?
The atomic number of nitrogen is 7. Nitrogen-15 is heavier than
nitrogen-14 because the atomic nucleus of nitrogen-15 contains how
Electrons exist only at fixed levels of potential energy. However, if
an atom absorbs sufficient energy, a possible result is that
The atomic number of neon is 10. Therefore, which of the following is
most correct about an atom of neon?
From its atomic number of 15, it is possible to predict that the
phosphorus atom has
Atoms whose outer electron shells contain 8 electrons tend to
The atomic number of each atom is given to the left of each of the
elements below. Which of the atoms has the same valence as carbon
Two atoms appear to have the same mass number. These atoms
Fluorine has an atomic number of 9 and a mass number of 19. How many
electrons are needed to complete the valence shell of a fluorine atom?
24) What is the maximum number of electrons in a single 2 p orbital
of an atom?
The organic molecules in living organisms have a measurably lower
ratio of carbon-13/carbon-12, two stable isotopes of carbon that
comprise approximately 1.1% and 98.9% of atmospheric carbon,
respectively. What is a reasonable explanation for this phenomenon?
Phosphorus-32, a radioactive isotope of phosphorus-31 (atomic number
15), undergoes a form of radioactive decay whereby a neutron turns
into a proton and emits radiation in the form of an electron. What is
the product of such radioactive decay of phosphorus-32?
An atom with atomic number 12 would have what type of chemical
behavior in bonding with other elements?
If a salamander relied on hydrogen bonds to cling to surfaces, what
type of surface would cause the most problems for this animal?
A covalent chemical bond is one in which
What is the maximum number of covalent bonds an element with atomic
number 8 can make with hydrogen?
Nitrogen (N) is much more electronegative than hydrogen (H). Which of
the following statements is correct about the atoms in ammonia (NH₃)?
When two atoms are equally electronegative, they will interact to
What results from an unequal sharing of electrons between atoms?
A covalent bond is likely to be polar when
Which of the following molecules contains the most polar covalent
In comparing covalent bonds and ionic bonds, which of the following
would you expect?
What is the difference between covalent bonds and ionic bonds?
In ammonium chloride salt (NH₄Cl) the anion is a single chloride ion,
Cl. What is the cation of NH₄Cl?
The atomic number of chlorine is 17. The atomic number of magnesium
is 12. What is the formula for magnesium chloride?
How many electron pairs are shared between carbon atoms in a molecule
that has the formula C₂H₄?
Which bond or interaction would be difficult to disrupt when
compounds are put into water?
Which of the following explains most specifically the attraction of
water molecules to one another?
Van der Waals interactions result when
What bonding or interaction is most likely to occur among a broad
array of molecules of various types (polar, nonpolar, hydrophilic,
Which of the following is not considered to be a weak molecular
Which of the following would be regarded as compounds?
What is the maximum number of hydrogen atoms that can be covalently
bonded in a molecule containing two carbon atoms?
of the following is true for this reaction?
Which of the following correctly describes chemical equilibrium?
Which of the following correctly describes any reaction that has
reached chemical equilibrium?
Which of these systems is least likely to be at chemical equilibrium?
group of molecular biologists is trying to synthesize a new
artificial compound to mimic the effects of a known hormone that
influences sexual behavior. They have turned to you for advice. Which
of the following compounds is most likely to mimic the effects of the
In the term trace element, the modifier trace means that
Compared with ³¹P, the radioactive isotope ³²P has
The reactivity of an atom arises from
Which statement is true of all atoms that are anions?
Which of the following statements correctly describes any chemical
reaction that has reached equilibrium?
We can represent atoms by listing the number of protons, neutrons,
and electrons: for example,
The atomic number of sulfur is 16. Sulfur combines with hydrogen by
covalent bonding to form a compound, hydrogen sulfide. Based on the
number of valence electrons in a sulfur atom, predict the molecular
formula of the compound:
What coefficients must be placed in the following blanks so that all
atoms are accounted for in the products?