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)
An irrational number is a real number that cannot be written as a simple fraction.
4 = 4/1 = rational
0 = 0/1 = rational
-2/3 = rational
4.11111 = irrational
2 = 2/1 = rational
π = 3.141592... = irrational
√6= irrational
Answer:
4.1111, π , √6
An ion is created by the transfer of electrons. The metals give away the elections and become positively charged. The non - metals take on electrons.
Balance.
So an ion is any atom that either gives away or takes on electrons.
Solution:
initial sphere mvr = final sphere mvr + Iω
where I = mL²/3 = 2.3g * (2m)² / 3 = 3.07 kg·m²
0.25kg * (12.5 + 9.5)m/s * (4/5)2m = 3.07 kg·m² * ω
where: ω = 2.87 rad/s
So for the rod, initial E = KE = ½Iω² = ½ * 3.07kg·m² * (2.87rad/s)²
E = 12.64 J becomes PE = mgh, so
12.64 J = 2.3 kg * 9.8m/s² * h
h = 0.29 m
h = L(1 - cosΘ) → where here L is the distance to the CM
0.03m = 1m(1 - cosΘ) = 1m - 1m*cosΘ
Θ = arccos((1-0.29)/1) = 44.77 º
Similarity : inverse square law for strength of force compared with distance.