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문제 44a
Give molecular formulas corresponding to each of the following ball-and-stick molecular representations (red = O, gray = C, blue = N, ivory = H). In writing the formula, list the elements in alphabetical order. (a) Alanine (an amino acid)
문제 44b
Give molecular formulas corresponding to each of the following ball-and-stick molecular representations (red = O, gray = C, blue = N, ivory = H). In writing the formula, list the elements in alphabetical order. (b) Ethylene glycol (automobile antifreeze)
문제 44c
Give molecular formulas corresponding to each of the following ball-and-stick molecular representations (red = O, gray = C, blue = N, ivory = H). In writing the formula, list the elements in alphabetical order. (c) Acetic acid (vinegar)
- How many elements are presently known? About how many occur naturally?
문제 46
문제 46a
What are the molecular weights of the following pharmaceuticals? (a) C33H35FN2O5 (atorvastatin, lowers blood cholesterol)
- Which element accounts for roughly 75% of the observed mass of the universe? Which four elements make up 95% of the mass of the human body?
문제 47
- Look at the alphabetical list of elements inside the front cover. What are the symbols for the following elements? (a) Gadolinium (used in color TV screens) (b) Germanium (used in semiconductors) (c) Technetium (used in biomedical imaging) (d) Arsenic (used in pesticides)
문제 48
- Look at the alphabetical list of elements inside the front cover. What are the symbols for the following elements? (a) Cadmium (used in rechargeable Ni-cad batteries) (b) Iridium (used for hardening alloys) (c) Beryllium (used in the space shuttle) (d) Tungsten (used in light bulbs)
문제 49
- Look at the alphabetical list of elements inside the front cover. Give the names corresponding to the following symbols: (a) Te (b) Re (c) Be (d) Ar (e) Pu
문제 50
- Look at the alphabetical list of elements inside the front cover. Give the names corresponding to the following symbols: (a) B (b) Rh (c) Cf (d) Os (e) Ga
문제 51
- What is wrong with each of the following statements? (a) The symbol for tin is Ti. (b) The symbol for manganese is Mg. (c) The symbol for potassium is Po. (d) The symbol for helium is HE.
문제 52
- What is wrong with each of the following statements? (a) The symbol for carbon is ca. (b) The symbol for sodium is So. (c) The symbol for nitrogen is Ni. (d) The symbol for chlorine is Cr
문제 53
문제 54a
Examine Figure 2.2, A portion of Mendeleev's periodic table. (a) Which characteristic was used to organize the elements in the table?
문제 54b
Examine Figure 2.2, A portion of Mendeleev's periodic table. How was Mendeleev able to predict with a high level of accuracy the properties of the undiscovered elements beneath Al and Si in the periodic table?
문제 55f
Examine Figure 2.3, The periodic table. (f) Classify the following three elements as metals, nonmet-als, or semimetals: Mo, Br, Si.
문제 55g
Examine Figure 2.3, The periodic table. (g) What is the symbol for the element located in period 3, group 4A?
- What are the rows called and what are the columns called in the periodic table?
문제 56
- How many groups are there in the periodic table? How are they labeled?
문제 57
- What common characteristics do elements within a group of the periodic table have?
문제 58
- Where in the periodic table are the main-group elements found? Where are the transition metal groups found?
문제 59
- Where in the periodic table are the metallic elements found? Where are the nonmetallic elements found?
문제 60
- What is a semimetal, and where in the periodic table are semimetals found?
문제 61
- Classify the following elements as metals, nonmetals, or semimetals: (a) Ti (b) Te (c) Se (d) Sc (e) Si
문제 62
- Classify the following elements as metals, nonmetals, or semimetals: (a) Ar (b) Sb (c) Mo (d) Cl (e) N (f) Mg
문제 63
- List several general properties of the following groups: (a) Alkali metals (b) Noble gases (c) Halogens
문제 64
문제 65a
(a) Without looking at a periodic table, list as many alkali metals as you can. (There are five common ones.)
문제 65b
(b) Without looking at a periodic table, list as many alkaline earth metals as you can. (There are five common ones.)
- Without looking at a periodic table, list as many halogens as you can. (There are four common ones.)
문제 66
- Without looking at a periodic table, list as many noble gases as you can. (There are six common ones.)
문제 67
- At room temperature, a certain element is found to be a soft, silver-colored solid that reacts violently with water and is a good conductor of electricity. Is the element likely to be a metal, a nonmetal, or a semimetal?
문제 68