Number of atoms : 1.26 x 10²³
<h3>Further explanation </h3>
The mole is the number of particles(molecules, atoms, ions) contained in a substance
1 mol = 6.02.10²³ particles
Can be formulated
N=n x No
N = number of particles
n = mol
No = Avogadro's = 6.02.10²³
0.21 moles of Al, so n = 0.21
Number of atoms :
![\tt N=0.21\times 6.02\times 10^{23}\\\\N=1.26\times 10^{23}](https://tex.z-dn.net/?f=%5Ctt%20N%3D0.21%5Ctimes%206.02%5Ctimes%2010%5E%7B23%7D%5C%5C%5C%5CN%3D1.26%5Ctimes%2010%5E%7B23%7D)
Option A is correct answer.
According to octet rule, atoms have tendency to lose, gain and share electrons to complete its octet i.e. eight valence electrons are surrounded to the atom.
Since, sulphur contains six valence electrons and two chlorine atoms are present in the reaction having seven valence electrons. Thus, to complete their octet, chlorine shares a pair of electrons with the sulphur atom.
<span>(3) amina ........................</span>
N₂ + 3H₂ ⇒ 2NH₃
1mol : 2mol
3,72mol : 7,44mol
n = 7,44mol
M = 17g/mol
m = n * M = 7,44mol * 17g/mol = 126,48g