No, the formation of dew is condensation, which is a physical change.
Reactivity trends of halogen:
1) Melting point and boiling points increased down the
group
2) Colour becomes darker.
E.g. Fluorine (pale yellow)
Chlorine (yellowish-green)
Bromine (reddish-brown)
Iodine (purplish-black)
Astatine (black)
3) The reactivity decreases down the group.
Reactivity:
F > Cl > Br > I > At
Answer:
265.2amu
Explanation:
Given parameters:
Atomic mass = 254.9amu
Abundance of isotope 1 = 72%
Atomic mass of isotope 1 = 250.9amu
Abundance of isotope 2 = 100 - 72 = 28%
Unknown:
Atomic mass of isotope 2 = ?
Solution:
To find the atomic mass of isotope 2, use the expression below:
Atomic mass = (abundance of isotope 1 x atomic mass of isotope 1) + (abundance of isotope 2 x atomic mass of isotope 2)
Now insert the parameters and find the unknown;
254.9 = (0.72 x 250.9) + (0.28 x Atomic mass of isotope 2)
254.9 = 180.648 + 0.28x atomic mass of isotope 2
254.9 - 180.648 = 0.28x atomic mass of isotope 2
74.25 = 0.28 x atomic mass of isotope 2
Atomic mass of isotope 2 = 265.2amu
