To know if elements have the same number of valence electrons you can look at what group they are in on the periodic table. Rubidium (Rb) is in group one which means it will have the same number on valence electrons as Lithium (Li) because Lithium is also in group one on the periodic table. I hope this helps!!
Answer:
Jupiter and Saturn will come within 0.1 degrees of each other, forming the first visible "double planet" in 800 years.
Explanation:
The 2020 great conjunction is especially rare, the planets haven't been this close together in nearly 400 years, and haven't been observable this close together at night since medieval times, in 1226.
It takes the moon 27 days and 8 hours
The ability of a telescope to separate two closely spaced stars is called (angular) resolution.
What is a telescope ?
Astronomers use a telescope to observe distant things. Curved mirrors are used by the majority of telescopes, including all large telescopes, to collect and concentrate light from the night sky. The original telescopes employed lenses, which are simply curved pieces of clear glass, to focus light.
The capacity of a telescope to distinguish two point sources into distinct pictures is known as resolution. The resolving power is constrained by diffraction effects in ideal circumstances, such as above the atmosphere where there is no turbulence (seeing).
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