How many inner shell electrons does a atom of 1s2 2s2 2p6 3s2 3p4 have ?

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.

How are isotopes of the same chemical element alike? how are they different?

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space