How many lone pairs of electrons are on the central atom in the lewis structure of carbon dioxide? 0, 1, 2, or 3?

The percent isotopic abundance of Cu-65 is 30.79 %.

The percent isotopic abundance of Cu-63 is 69.21 %.

Explanation:

we know there are two naturally occurring isotopes of carbon, Cu-63 (62.9298 amu)  and Cu-65 (64.9278 amu)

First of all we will set the fraction for both isotopes

X for the isotopes having mass 62.9298 amu

1-x for isotopes having mass 64.9278 amu

The average atomic mass of copper is 63.546 amu.

we will use the following equation,

62.9298 x + 64.9278 (1-x) = 63.546

62.9298x +  64.9278 -  64.9278x = 63.546

62.9298x - 64.9278x = 63.546  - 64.9278

-1.998 x = -1.3828

x=-1.3828 / -1.998

x= 0.6921

0.6921 × 100 = 69.21 %

69.21 % is abundance of Cu-63 because we solve the fraction x.

now we will calculate the abundance of Cu-65.

(1-x)

1-0.6921 = 0.3079

0.3079 × 100 = 30.79 %

30.79 % for Cu-65.