Elements are organized on the periodic table by there atomic mass

true or false?

That's false.

Explanation:

The elements are organized by atomic number, not atomic mass. The atomic mass measure is inaccurate in one case. Iodine (53) has a smaller atomic mass than tellurium (52) (126.9 compared to 127.6.), although it is the element after tellurium.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.