Please please please need asap which element will have the same number of core electrons as a Sodium atom?

There is one girl i like and i don't know how to tell her that, i have a feeling she knows but if she doesn't i don't want to make a fool out of myself how is one way to boost my confidence on asking her out

In the space, show a correct numerical setup for calculating the number of moles of co2 present in 11 grams of co2

The element chlorine has two stable isotopes, chlorine-35 with a mass of 34.97 amu and chlorine-37 with a mass of 36.95 amu. from the atomic weight of cl = 35.45 one can conclude that: