If you count the number of electrons (small dots), you have the atomic number. In this case you have 11 so this atom is a sodium atom. Sodium has 1 valence electron (electron on the outer shell) and chlorine has 7. This means that if sodium gave one electron away and chlorine would obtain one electron, they would both have the (ideal) noble gas conformation (full outer shell).
Answer:
it would increase to twice what it was
It is elastic potential energy
Refer to the diagram shown below.
The piston supports the same load W at both temperatures.
The ideal gas law is

where
p = pressure
V = volume
n = moles
T = temperature
R = gas constant
State 1:
T₁ = 20 C = 20+273 = 293 K
d₁ = 25 cm piston diameter
State 2:
T₂ = 150 C = 423 K
d₂ = piston diameter
Because V, n, and R remain the same between the two temperatures, therefore

If the supported load is W kg, then

Similarly,


Because p₁/p₂ = T₁/T₂, therefore

The minimum piston diameter at 150 C is 20.8 cm.
Answer: 20.8 cm diameter