Q46P - Chemistry: Molecular Nature Of Matter And Change

Question

Draw atomic depictions similar to those in Problem 2.43 for  $\mathbf{\left(}\mathit{a}\mathbf{\right)}\mathbf{ }{}_{\mathbf{82}}{}^{\mathbf{207}}\mathit{P}\mathit{b}\mathbf{ }\mathbf{\left(}\mathit{b}\mathbf{\right)}\mathbf{ }{}_{\mathbf{5}}{}^{\mathbf{9}}\mathit{B}\mathit{e}\mathbf{ }\mathbf{\left(}\mathit{c}\mathbf{\right)}\mathbf{ }{}_{\mathbf{33}}{}^{\mathbf{75}}\mathit{A}\mathit{s}$

Step-by-Step Solution

Answer

In an element A represents the mass number and while Z represents an atomic number of an element.

(a)(b)(c)

Step 1 Solution for part (a)

${}_{82}{}^{207}Pb$

Given,

Atomic number = 82

Atomic mass = 207

Number of protons = Atomic number = 82

Number of electrons = 82

We know, 

Atomic mass = number of protons + number of neutrons

So,

Number of neutrons = atomic mass – number of protons

Number of neutrons = 207 – 82 = 125

 

Step 2 Solution for part (b)

${}_5{}^{9}Be$

Given,

Atomic number = 5

Atomic mass = 9 

Number of protons = Atomic number = 5

Number of electrons = 5

We know, 

Atomic mass = number of protons + number of neutrons 

So,

Number of neutrons = atomic mass – number of protons

Number of neutrons = 9 – 5 = 4

Step 3 Solution for part (c)

${}_{33}{}^{75}As$

Given,

Atomic number = 33

Atomic mass = 75

Number of protons = Atomic number = 33

Number of electrons = 33

We know, 

Atomic mass = number of protons + number of neutrons

So,

Number of neutrons = atomic mass – number of protons

Number of neutrons = 75 – 33 = 42