Question

The atom with the same number of neutrons as 12c is

Answer 1

11B 

12C = 6 protons and 6 neutrons. 
11B = 5 protons and 6 neutrons. 
13C = 6 protons and 7 neutrons,

Answer 2

Answer is: boron (¹¹B).

1)  Carbon (¹²C) is element with atomic number 6 and mass number 12. Atomic number (Z) is the number of protons, which is characteristic of a chemical element.

Z(C) = p⁺ = 6.

A = p⁺ + n°; mass number is the total number of protons and neutrons in a nucleus.  

A(C) = 12.

n°(C) = 12 - 6.

n°(C) = 6; number of neutrons.

2) Boron (¹¹B) is element with atomic number 5 and mass number 11.

Z(B) = p⁺ = 5.

A(B) = 11.

n°(B) = 11 - 5.

n°(B) = 6; number of neutrons in boron.