Answer:
It is Distance (meters)
between seconds 3 and 4
Explanation:
I had this on my test last week
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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<span>When a cell is in a dynamic equilibrium with its environment, this means that the salt/water concentration inside the cell is equal to the salt/water concentration outside the cell. It is called an equilibrium because no transport of molecules is needed since the concentrations are already the same.</span>
