How can a student use a diagram to calculate the atomic mass for the helium atom

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.

Abaker touches a pie right after taking it out of the oven. which statement best explains why the pie feels hot?

20 grams of water. she poured out 15 grams. which of the following physical properties of the water changes? a .boiling point b. density c .electrical conductivity d .volume