Mendeleev found that when he arranged the known elements according to their atomic mass, the entries in the table exhibited a pattern of chemical properties that repeated itself in groups of eight elements. This led to the generalization now known as:
A. an atomic model.
B. the periodic table.
C. valance electrons.
D. the octet rule.
Answer: D
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Carbon monoxide ____
a. traps heat in the atmosphere b. is an atmospheric pollutant c. causes acid rain d. interferes with the nervous system e. binds to a hemoglobin molecule and interferes with oxygen uptake
The photosystem channels the excitation energy gathered by absorption of light by any one of the pigment molecules to a specific reaction center chlorophyll, which in turn passes the energy to
A. photosystem II. B. cytochrome. C. photosystem I. D. the secondary electron center. E. the primary electron acceptor.
What does phototaxis allow the cell to do?
a. stay in the optimum light environment b. stay in the optimum magnetic environment c. stay in the optimum chemical environment d. stay in the optimum climate environment
Human females with XY chromosomes and a phenotype that includes the absence of a uterus and ovaries and the presence of testes are likely to have which of the following mutations?
A. a deletion that removes much of the Y chromosome B. a defect in a gene involved in X inactivation C. a mutation in the androgen receptor gene D. They likely do not carry a mutation but may have been premature babies. E. a mutation in the SRY gene