How are the salt ducts an adaptation to the iguanas’ environment?

Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in the n=3 level to an orbital in the n=7 level.

Alarge marble is dropped in a graduated cylinder with 35ml of water in it.the water level increases to 49ml.what is the volume of the marble

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.