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
The nucleus of an atom contain neutrons and protons, and energy levels surround the nucleus, in rings and contain electrons
Answer: A wavelenghth is the<u> distance between successive crests</u> of one <u>wave</u>.
Answer:
<em>fractional distillation</em><em> </em><em>is</em><em> </em><em>the</em><em> </em><em>most common method for air separation</em><em>.</em>
