Answer the following question given this paragraph: low, the two metals with the highest ionization energies (beryllium and magnesium) do form compounds that exhibit some covalent characters. Like the alkali metals, the heavier alkaline earth metals impart color to a flame. As in the case of the alkali metals, this is part of the emission spectrum of these elements. Calcium and strontium produce shades of red, whereas barium produces a green color. Magnesium is a silver-white metal that is malleable and ductile at high temperatures. Passivation decreases the reactivity of magnesium metal. Upon exposure to air, a tightly adhering layer of magnesium oxycarbonate forms on the surface of the metal and inhibits further reaction. (The carbonate comes from the reaction of carbon dioxide in the atmosphere. ) Magnesium is the lightest of the widely used structural metals, which is why most magnesium production is for lightweight alloys. Magnesium (shown in Figure 18.6), calcium, strontium, and barium react with water and air. At room temperature, barium shows the most vigorous reaction. The products of the reaction with water are hydrogen and the metal hydroxide. The formation of hydrogen gas indicates that the heavier alkaline earth metals are better reducing agents (more easily oxidized) than is hydrogen. As expected, these metals react with both acids and nonmetals to form ionic compounds. Unlike most salts of the alkali metals, many of the common salts of the alkaline earth metals are insoluble in water because of the high lattice energies of these compounds, containing a divalent metal ion. Q: Which is the lightest of the widely used structural metals? Choices: - Metal - calcium - potassium - magnesium A:
magnesium
(Question)
Answer the following question given this paragraph: The force that a magnet exerts is called magnetic force. The force is exerted over a distance and includes forces of attraction and repulsion. A magnet can exert force over a distance because the magnet is surrounded by a magnetic field. Q: What force includes forces of attraction and repulsion? Choices: - centripetal force - gravitational force - molecular force - magnetic force A:
(Answer)
magnetic force
Ques: Answer the following question given this paragraph: Q: How does water from roots reach the leaves? Choices: - water - combining cells - water - raising cells - water-phobic cells - water-conducting cells A:
Ans: water-conducting cells
(Q).
Answer the following question given this paragraph: The aphotic zone is water deeper than 200 meters. This is where too little sunlight penetrates for photosynthesis to occur. As a result, producers must make "food" by chemosynthesis , or the food must drift down from the water above. Q: What is the name of the zone where water is deeper than 200 meters called? Choices: - transition zone - euphotic zone - eccentric zone - aphotic zone A:
(A).
aphotic zone
Ques:Answer the following question given this paragraph: Decomposition of dead organisms and organic wastes releases carbon back to the atmosphere, soil, or ocean. Q: What does the decomposition of dead organisms and organic waste release into the atmosphere, soil, or ocean? Choices: - nitrogen - oxygen - hydrogen - carbon A:

Ans:carbon
Question: Answer the following question given this paragraph: In science, motion is defined as a change in position. An object's position is its location. Besides the wings of the hummingbird in the opening image, you can see other examples of motion in the Figure below . In each case, the position of something is changing. Q: In science, what is defined as a change in position? Choices: - gravity - speed - direction - motion A:
Answer:
motion