A solution that is 0.024 M in Na+ can be prepared by adding how many grams of Na2SO4 (MW 142 g) to water and diluting to a final
volume of 140.0 mL?
1. 0.00024 g
2. 0.24 g
3. 95 g
4. 0.48 g
5. 0.0095 g

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

since electrons are negative the answer is neagtaive

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8