An element P has two isotopes with relative abundance of 65% and 35%. If the mass number of the two isotopes is X and 31 respectively, find the mass number represented by X given that the relative atomic mass of element P is 30.

29.5

Explanation:

Given parameters:

Abundance of P- 30 = 65%  = 0.65

Abundance of P-31  = 35%  = 0.35

Mass number of P-30 = X

Mass number of P - 31  = 31

Relative atomic mass of substance  = 30

Unknown:

Mass number of P-30

Solution:

To solve this problem, apply the formula below;

  R.A.M  = (mass number of P-30  x Abundance of P-30) + (mass number of P-30 x abundance of P-31)

 Now insert the parameters and solve for X;

 30  = (X x  0.65) + (31 x 0.35)

 30 = 0.65X + 10.85

  30 - 10.85 = 0.65X

    19.15 = 0.65X

     X  = 29.5

trigonal pyramidal

tetrahedral

trigonal planar

bent

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be