What is the difference between atomic number and atomic mass, and what do they tell you about the atom

Mass number is the number of protons and neutrons in an atom, and it tells us about the mass of the atom in amu, or atomic mass units.

Atomic mass is the average mass of all the isotopes of a certain type

answer; i believe the correct answer is (c) /// is a homogeneous mixture of gaseous substance nitrogen,oxygen and smaller amounts of other substancesmixtures can be either ( homogeneous or heterogeneous)plz check first good luck

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year