What is the formula used to calculate the number of neutrons in an atom

The p sub shell can hold up to 8 electrons in an atom. true or false?

Needthe meter is the standard unit for: 1) height 2) length 3) weight 4) mass

Assuming complete dissociation of the solute, how many grams of kno3 must be added to 275 ml of water to produce a solution that freezes at -14.5 c? the freezing point for pure water is 0.0 c and k_f is equal to 1.86 c/m