How are regular carbon, carbon 11, and carbon 14 the same?

They have the same number of protons and neutrons .

Explanation :

Carbon, Carbon 11 and Carbon 14 are Isotopes ( Isotopes are forms of an element that have the same number of protons and electrons but different numbers of neutrons ) . Isotopes have the same atomic number.

I hope this helps.

it should be all of them because it asks if you included all of those in your answer

explanation:

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally