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:
Given
speed of Electron 
final speed of Electron 
distance traveled 
using equation of motion

where v=Final velocity
u=initial velocity
a=acceleration
s=displacement


acceleration is given by 
where q=charge of electron
m=mass of electron
E=electric Field strength

Answer:
Explanation:
A ) When gymnast is motionless , he is in equilibrium
T = mg
= 63 x 9.81
= 618.03 N
B )
When gymnast climbs up at a constant rate , he is still in equilibrium ie net force acting on it is zero as acceleration is zero.
T = mg
= 618.03 N
C ) If the gymnast climbs up the rope with an upward acceleration of magnitude 0.600 m/s2
Net force on it = T - mg , acting in upward direction
T - mg = m a
T = mg + m a
= m ( g + a )
= 63 ( 9.81 + .6)
= 655.83 N
D ) If the gymnast slides down the rope with a downward acceleration of magnitude 0.600 m/s2
Net force acting in downward direction
mg - T = ma
T = m ( g - a )
= 63 x ( 9.81 - .6 )
= 580.23 N
When drinking at a private event, you should assume that drinks will be STRONGER THAN NORMAL.
At private events, some hosts have the habit of mixing different drinks together in order to increase the intoxicating power of the drinks. This does not normally happen when one is buying from restaurants or other commercial places. Thus, to be on the safe side, one should always assume that drinks will be stronger when one is attending a private event, this will caution one to drink responsibly in order to avoid intoxication.
This because your face has more sensitive tissue than anywhere else in your body
Hope this helps