Do 1 mole of sodium and calcium have different number of atoms ?

A ballon has 5.0 g mole of helium at 7^@C calculate the number of atoms of helium in the ballon.

What is the role of sodium and calcium in the permeability of membrane?

Do 1 mole of Na and O_2 have same mass?

Which one of the following will have largest number of atoms?

In three moles of ethane. calculate the number of moles of carbon atoms.

In three moles of ethane. calculate the number of moles of hydrogen atoms.

Sodium and aluminium have atomic numbers of 11 and 13 respectively they are separated by one element in the periodic table and have valencies of 1 and 3 respectively. chlorine and potassium are also separated by one element in the periodic table(their atomic numbers are 17 and 19 respectively) and yet both have valency of one. explain your answer

Electromagnetic radiation of wavelength 242 nm is just sufficient to ionise the sodium atom, Calculate the ionisation energy of sodium is KJ mol ^(-1).