Rubidium is an element that belongs to Group 1. As such it will have physical properties similar to the other Group 1 elements. Rubidium is below
Potassium in the periodic table but above
Cesium. As such it would be most like one of those two elements.
Answer : The fuel value and the fuel density of pentane is, 49.09 kJ/g and
respectively.
Explanation :
Fuel value : It is defined as the amount of energy released from the combustion of hydrocarbon fuels. The fuel value always in positive and in kilojoule per gram (kJ/g).
As we are given that:

Fuel value = 
Molar mass of pentane = 72 g/mol
Fuel value = 
Fuel value = 49.09 kJ/g
Now we have to calculate the fuel density of pentane.
Fuel density = Fuel value × Density
Fuel density = (49.09 kJ/g) × (0.626g/mL)
Fuel density = 30.73 kJ/mL = 
Thus, the fuel density of pentane is 
Because they are coming from the ground and always safe
<span>What is the electron configuration of aluminum is </span>1s^2 2s^2 2p^6 3s^2 3p^1.