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.
Please mark brainliest if I helped you!
Answer:
A
Explanation:
If you can define photosynthesis..
<span>This organelle is the nucleolus.
The nucleolus is made of proteins, DNA, and RNA. They form around specific regions of the chromosomes called nucleolar organizing regions. These regions of the chromosomes contain some the genes needed for ribosome production.</span>
The first one i think it is the first one
