Answer the following question given this paragraph: valence shell is called the octet rule. When atoms form compounds, the octet rule is not always satisfied for all atoms at all times, but it is a very good rule of thumb for understanding the kinds of bonding arrangements that atoms can make. It is not impossible to violate the octet rule. Consider sodium: in its elemental form, it has one valence electron and is stable. It is rather reactive, however, and does not require a lot of energy to remove that electron to make the Na+ ion. We could remove another electron by adding even more energy to the ion, to make the Na2+ ion. However, that requires much more energy than is normally available in chemical reactions, so sodium stops at a 1+ charge after losing a single electron. It turns out that the Na+ ion has a complete octet in its new valence shell, the n = 2 shell, which satisfies the octet rule. The octet rule is a result of trends in energies and is useful in explaining why atoms form the ions that they do. Now consider an Na atom in the presence of a Cl atom. The two atoms have these Lewis electron dot diagrams and electron configurations:. Q: Which rule is a result of trends in energies and is useful in explaining why atoms form the ions that they do? Choices: - electrons rule - nutron rule - coupling rule - octet rule A:
octet rule
Answer the following question given this paragraph: Second, plant cells have a cell wall , while animal cells do not ( Figure below ). The cell wall surrounds the plasma membrane but does not keep substances from entering or leaving the cell. A cell wall gives the plant cell strength and protection. Q: What gives the plant cell strength and protection? Choices: - the protons - the cell nucleus - the genes - a cell wall A:
a cell wall
Q: Answer the following question given this paragraph: Hemophilia is a group of diseases in which blood does not clot normally. Factors in blood are involved in clotting. When you bleed, your body begins a coagulation cascade of reactions, involving special proteins known as coagulation factors, to stop that bleeding. When one or more of these clotting factors are missing, there is a higher chance of having dificulties stoping the bleeding. Hemophiliacs lacking the normal Factor VIII are said to have Hemophilia A (or Factor VIII deficiency), the most common form. Hemophilia is a genetic disease, passed down through family. It is linked to the X-chromosome, so it mostly affects males. F8 is the gene for the Factor VIII protein. Mutations in the F8 gene lead to the production of an abnormal version of coagulation factor VIII, or reduce the amount of the protein. The altered or missing protein cannot participate effectively in the blood clotting process. Q: What is the term for diseases in which blood does not clot normally? Choices: - arthritis - diabetes - lymphoma - hemophilia A:
A: hemophilia
Question: Answer the following question given this paragraph: A binary molecular compound is a molecular compound that is composed of two elements. In general, the elements that combine to form binary molecular compounds are both nonmetals. This contrasts with ionic compounds, which usually involve bonds between metal ions and nonmetal ions. Because ionic charges cannot be used to name these compounds or to write their formulas, a different naming system must be used for molecular compounds. Another difference between ionic and molecular compounds is that two nonmetal atoms will frequently combine with one another in a variety of ratios. For example, nitrogen and oxygen combine to make several binary compounds, including NO, NO 2 , and N 2 O. Obviously they can't all be called nitrogen oxide! How would someone know which one you were talking about? Each of the three compounds has very different properties and reactivity. A system to distinguish between compounds such as these is necessary. Q: A binary molecular compound is a molecular compound that is composed of what? Choices: - two atoms - four atoms - four elements - two elements A:
Answer: two elements
*Question*
Answer the following question given this paragraph: Population density is the average number of individuals per unit of area or volume. Q: The average number of individuals per unit of area or volume is referred to as a population's what? Choices: - increase - diameter - output - density A:
**Answer**
density
(Question)
Answer the following question given this paragraph: Figure 27.1 The leaf chameleon (Brookesia micra) was discovered in northern Madagascar in 2012. At just over one inch long, it is the smallest known chameleon. (credit: modification of work by Frank Glaw, et al. , PLOS). Q: The leaf chameleon (brookesia micra) was discovered in northern madagascar in 2012. at just over one inch long, it is what? Choices: - first known chameleon - largest chameleon - hottest known chameleon - smallest known chameleon A:
(Answer)
smallest known chameleon