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Problem 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)
Problem 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)
Problem 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?
Problem 46
Problem 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?
Problem 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)
Problem 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)
Problem 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
Problem 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
Problem 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.
Problem 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
Problem 53
Problem 54a
Examine Figure 2.2, A portion of Mendeleev's periodic table. (a) Which characteristic was used to organize the elements in the table?
Problem 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?
Problem 55f
Examine Figure 2.3, The periodic table. (f) Classify the following three elements as metals, nonmet-als, or semimetals: Mo, Br, Si.
Problem 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?
Problem 56
- How many groups are there in the periodic table? How are they labeled?
Problem 57
- What common characteristics do elements within a group of the periodic table have?
Problem 58
- Where in the periodic table are the main-group elements found? Where are the transition metal groups found?
Problem 59
- Where in the periodic table are the metallic elements found? Where are the nonmetallic elements found?
Problem 60
- What is a semimetal, and where in the periodic table are semimetals found?
Problem 61
- Classify the following elements as metals, nonmetals, or semimetals: (a) Ti (b) Te (c) Se (d) Sc (e) Si
Problem 62
- Classify the following elements as metals, nonmetals, or semimetals: (a) Ar (b) Sb (c) Mo (d) Cl (e) N (f) Mg
Problem 63
- List several general properties of the following groups: (a) Alkali metals (b) Noble gases (c) Halogens
Problem 64
Problem 65a
(a) Without looking at a periodic table, list as many alkali metals as you can. (There are five common ones.)
Problem 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.)
Problem 66
- Without looking at a periodic table, list as many noble gases as you can. (There are six common ones.)
Problem 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?
Problem 68