Atomic mass number is the number of protons and neutrons. Subtract 80-35=45 is the number of protons. Because the atom is neutrally charged, the number of protons must equal the number of electrons, so there are 45 electrons.
Answer:
Chemical change :has change in mass, heat is needed, new element is formed, hard to reverse.......
Physicalchange:does not have change in mass, heat is not necessary, no new element is formed, easy to reverse
Answer: Butane will effuse more quickly because it has a smaller molar mass
Explanation:
Molar mass of C4H10 = 58.123 g/mole
Molar mass of I2 = 253.808 g/mole
I believe Neon is closest to Magnesium on the Periodic Table of elements.
Sorry if I'm wrong, hope I could help though! :)
Mg gained mass because it went from being a single element (on the reactant side) to being a molecule (on the product side).