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1) Evaluate the following statement: Oxygen is not a greenhouse gas; therefore, gases containing oxygen, such as ozone, nitrous oxide, and carbon dioxide, are not greenhouse gases either.
False. Compounds can have emergent properties that are very different from the elements that form them.
2) There are _____ naturally occurring elements.
3) Which of the following is a trace element?
4) What are the four most abundant elements found in living systems?
Carbon, Oxygen, Hydrogen, and Nitrogen
5) Which one of the following has negligible mass?
6)  Which one of the following subatomic particles has appreciable mass and lacks a charge?
7) The number of protons in an uncharged atom _____.
equals the number of electrosn
8) Consider a hypothetical atom with an atomic number of 4 and a net electronic charge of +1. How many neutrons does this atom have?
The answer cannot be determined from the information provided.
9) An element has 8 protons, 9 neutrons, and 8 electrons. Its atomic number and atomic mass, respectively, are _____.
8 and 17
10) An uncharged atom of nitrogen (atomic number = 7) has _____.
7 protons and 7 electrons
11) Isotopes of an element will always differ in _____.
Atomic mass
12)A particular carbon isotope has an atomic number of 6 and an atomic mass of 14. The respective number of neutrons, protons, and electrons that this carbon isotope has is _____
8, 6, and 6
13) Phosphorus-32 (radioactive) has _____ than phosphorus-35 (normal).
3 fewer neutrons
14) The most common form of calcium has 20 protons, 20 neutrons, and 20 electrons. Which of the following elements would be an isotope of calcium?
an atom with 20 protons, 21 neutrons, and 20 electrons
15) Radioactive isotopes are useful in scientific research because _______
They can be used as tracers to follow particular atoms and molecules through metabolic pathways.
16) Potassium (atomic number 19, mass number 40) and sodium (atomic number 11, mass number 23) have similar chemical properties and reactive behavior. This is because uncharged atoms of potassium and sodium _____.
have different mass numbers and each has 1 electron in its outermost electron shell
17) Atomic chlorine has an atomic number of 17. It has _____ electrons in its third shell.
18) The chemical characteristics or reactivity of an element depend mostly on the _____.
number of electrons in its outermost shell
19) Some groups of elements react chemically in similar ways. For example, the chemistry of sodium and the chemistry of lithium are similar. The chemistry of chlorine and the chemistry of iodine are also similar. These similarities in chemistry result when different elements have similar _____.
numbers of outer-shell electrons
20) How many electrons would be present in the valence shell of a sulfur atom (atomic number 16, mass number 32)?
6 electrons
21)  For most atoms, a stable configuration of electrons is attained when the atom _____.
has 8 electrons in its outermost shell
23) When one or more pairs of valence electrons are shared by two atoms, what type of bond is formed?
Covalent bond
22) An atom that normally has _____ in its outer shell would not tend to form chemical bonds with other atoms.
8 electrons
24) A polar covalent bond is a bond that _____.
has shared electrons pulled closer to the more electronegative atom
25) A covalent bond is likely to be polar if _____
one of the atoms sharing electrons is much more electronegative
26) When the proton number and electron number are unequal, the atom or molecule _____
is an ion
27) A sodium atom has a mass number of 23. Its atomic number is 11. How many electrons does it have if it is not an ion?
28) Copper has an atomic number of 29 and a mass number of 64. What would result if an uncharged copper atom lost two electrons?
The atomic number would remain 29, the mass number would remain 64, and the atom would be a cation with a +2 charge.
29) The compound CaSO4 ionizes into a calcium ion and a sulfate ion (SO4). Calcium has 2 electrons in its outer shell. Upon ionization, what would you expect the charge on the sulfate ion to be?
30)  Ionic bonds form as a result of _____.
attraction between ions that have opposite charges
31)  A hydrogen bond _____.
is a weak chemical bond
32) Hydrogen bonds occur when _____.
partial opposite charges on molecules come close enough to attract each other
33) What is the role of Van der Waals interactions in biological molecules?
Although they are weak bonds, Van der Waals interactions help to reinforce the 3-dimensional shapes of large molecules.
34) Which of the following molecules has the shape of a completed tetrahedron?
methane (CH4)
35) harmaceutical researchers are often interested in blocking particular receptor proteins on cell surfaces. What chemical property of a molecule would be most important for this type of application?
Molecules shape
36)  Which of the following statements is true about chemical reactions?
They involve the making and breaking of chemical bonds.
37) Which of the following statements describes a reversible reaction that has reached chemical equilibrium?
The rate of the reverse reaction equals the rate of the forward reaction.
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