The two are potassium and rubidium. Why? Na is an alkali metal. As you go down the metals become more reactive.
Calcium has 20 protons. Why? The atomic # is 20 (the one at the top).
It has 20 neutrons. Why? The atomic mass (the number on the bottom) is ~40, ignoring electron mass. 40- 20 protons = 20 neutrons.
It has 20 electrons.
Why? The # of protons and electrons is the same. Ions aren't on the periodic table.
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None of the above because they are non pollutant
<span>In
the desert food web shown below, which of the following best describes
the transfer of energy between the lubber grasshopper and the kangaroo
rat?
</span>
<span>C) About 10 percent of the kangaroo rat's energy transfers to the lubber grasshopper.
</span>
Answer:
elimination of synthetic pesticides and fertilizers and other materials, such as hormones and antibiotics, yield is typically lower in an organic field than for a similar crop grown in a conventional or GM cropping system, use of biological control, crop rotations and other techniques to manage weeds, insects and diseases.
Explanation:
i did the usa test prep :)
