Which of these statements is not true? Select one:
a. Atoms of the same element can have different masses
b. The nucleus of an atom has a positive charge
c. Atoms of isotopes of an element have different numbers of protons
d. Atoms are mostly empty space

C. Atoms of isotopes of an element have different numbers of protons

Explanation:

C. Atoms of isotopes of an element have different numbers of protons is correct/not true because isotopes are atoms of the same element that have a different number of NEUTRONS but same number of protons in the nucleus.

C.

Explanation:

C. Atoms of isotopes of an element have different numbers of protons is correct/not true because isotopes are atoms of the same element that have a different number of NEUTRONS but the same number of protons in the nucleus.

#Nova

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%