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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Hypothesis: If the tablet is placed in warm water, then the tablet will dissolve faster because an increase in temperature speeds up the dissolving rate of some substances.
Nitrogen fixation is a process that changes nitrogen within plants and soil into"nitrogen compounds"
They go to the brain then sent out to the rest of your body
Answer:
Q3:False, the oldest layers are found in the lower layers
Q2: A, a layer or a series of layers of rock in the ground
Q5: D
Q4: possibly D
Explanation:
