HALOGENS have 7 electrons in their final shell regardless if the total number of atoms. These 7 electrons would be shared between the 's' and 'p' orbital in the form
ns² np⁵ (the same as the question). Attached is a table that highlights the fact that halogens have the same form in terms of the valence electrons.
Explanation:
Moles of NaOH = 10g / (40g/mol) = 0.25mol.
0.25mol / 500g = 0.50mol / 1000g = 0.50mol/dm³.
The molarity is 0.50mol/dm³.
The arrangement of particles in a gas is random. they have no orderly arrangement and are free to move around while the particles in solid are in an orderly and rigid arrangement and cannot move about. particles in liquid are also arranged orderly but are not rigid
Chlorine has that electron configuration