Answer:
They can travel in a vacuum.
Explanation:
» Only electromagnetic waves travel through vacuum. The other mechanical waves require a material medium to travel.

On Earth, none of the atmosphere is.
This would be more of a chemistry question. Remember magnesium has a charge of 2+, and would need to hand off its two extra electrons. Fluorine can only take one electron at a time, so there needs to be two fluorines to take one magnesium's 2 electrons.
With lithium, it has a +1 charge, so it has one extra electron, which it can hand off to just 1 fluorine atom.
Another way of looking at this is:

+ 2

= MgF2 (the charges must balance out to zero)

+

= LiF (the charges balance out to zero)
Answer:

Explanation:
The time taken by the light to travel a given distance is defined as:

Here c is obviously the speed of light. Now we convert the average distance form Venus to Earth to meters:

Finally, we calculate the minutes taken by the light to travel from Venus to Earth:

The particles always move parallel and perpendicular to the waves. The waves which are in the water moves a circle. Both up and down and back and forth.
Good luck :)