Classify these salts as acidic, basic, or neutral. nh4clo4

How are elements arranged in a periodic table

Which is the layer underground where all empty spaces are filled with a combination of air and water ?

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