It would be an physical change ; if you melt butter the butter goes from a solid to a liquid so therefore the physical state is changed.
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:
The specific shape that an electron moves in inside a sub-level <em><u>shell</u></em><em><u>.</u></em>
UV rays, gamma rays, and x rays
Hope this help
