PRACTICE
1 Chlorine has two stable isotopes, chlorine-35 and chlorine-37. The
atomic number of chlorine is 17. Calculate the numbers of protons,
electrons, and neutrons each isotope has.

1. For isotope A (chlorine 35)

Proton = 17

Electron = 17

Neutron = 18

2. For isotope B (chlorine 37)

Proton = 17

Electron = 17

Neutron = 20

Explanation:

Let isotope A be chlorine-35

Let isotope B be chlorine-37

1. For isotope A (chlorine-35)

Data obtained from the question include:

Atomic number = 17

Mass number = 35

Proton number = atomi number

Proton number = 17

Since the isotope is neutral,

Electron number = proton number

Electron number = 17

Mass number = Neutron + proton

Neutron = Mass number - proton

Neutron = 35 - 17

Neutron number = 18

2. For isotope B (chlorine-37)

Data obtained from the question include:

Atomic number = 17

Mass number = 37

Proton number = atomi number

Proton number = 17

Since the isotope is neutral,

Electron number = proton number

Electron number = 17

Mass number = Neutron + proton

Neutron = Mass number - proton

Neutron = 37 - 17

Neutron number = 20

here we have to get the change of moles on decrease the volume of the reaction in gas phase.

the   per the given options it will decrease by (d) 11-50%

we know, on decreasing the volume of the gas phase reaction the reaction moves to the product side.

the reaction:                     so₂cl₂ (g) = so₂ (g) + cl₂ (g)         total

the moles at equilibrium:   1 - α                 α               α           = 1+α

concentrations:                   1 - α               α               α           = 1 + α

(concentration = moles/volume, as volume is 1 l)

(where α is the degree of dissociation)

now the dissociation constant in terms of concentration is :

=  

or,

or,   = (at v = 1l)

the reaction:                     so₂cl₂ (g) = so₂ (g) + cl₂ (g)         total

the moles at equilibrium:   1 - α                 α               α           = 1+α

concentrations:               (1 - α)/0.5           α/0.5         α/0.5       = (1 + α)/0.5

thus, the dissociation constant in terms of concentration is :

or,  

=  

so, the change of 1 : 1/0.5

or, 1: 2

thus it will decrease by 50%.

or, as per the given options it will decrease by 11-50%