It's either 1 or 4 (hfjsjhsjsjwjje)
1 hour I think.. correct me if im wrong <3
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:
Change in direction
Explanation:
"Rotation" refers to an object's spinning motion about its own axis. "Revolution" refers the object's orbital motion around another object.
