5.4 x 10²³ molecules
Explanation:
Given parameter
Volume of gas = 20L
Condition of reaction = STP
Unknown:
number of molecules
Solution:
The number of molecules of a substance is given by;
Number of molecules = Number of moles x avogadro's constant
Number of moles at stp = 
Number of moles of SO₂ = 
= 0.893mole
Number of molecules = 0.893 x 6.02 x 10²³ = 5.4 x 10²³ molecules
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Answer is: group 17 on the periodic table.
Group 17 (halogens) elements are: fluorine (F), chlorine (Cl), bromine (Br) and iodine (I).
They are very reactive and easily form many compounds.
Fluorine and chlorine are in gaseous state, bromine is liquid and iodine is in solid state in room temperature.
Halogens need to gain one electron to have electron cofiguration like next to it noble gas.
For example, fluorine has 9 electrons and it gain easily one electron in chemical reaction to have electron configuration like noble gas neon (Ne) with 10 electrons.
A 200 what? Then I can help!
On Earth it is relatively rare—5.2 ppm by volume in the atmosphere. Most terrestrial helium<span> present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of </span>helium<span>-4 nuclei.</span>
Answer:
melting point,boiling point ,density,refractive index.
Explanation:
