What limits the maximum amount of torque a motor can produce? The no load speed

The stall torque

The amount of current used to turn the motor

The type of controller used to operate the motors

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

the answer for sodium is 0.186

the answer for rubidium is 0.251

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.