What can you say about density if volume increase and mass stays the same

Density = mass
              volume 

For the sake of explanation, let's pretend the mass is 2g and the volume is 1 ml

Density = 2 g = 2 g/ml
              1 ml

Now if we increase the volume, and leave the mass the same then mass is still 2g, but we can increase the volume to 2 ml 

Density = 2 g   = 1 g/ml
              2 ml

Therefore we can say that if volume increases and mass stays the same, then density will decrease.

All the elements are arranged by melting points on the periodic table. in row they go from metals to gasses. in the row from sodium to argon, sodium is more reactive than the one on its right, magnesium.