Which part of the atom has to stay the same for it to be the same element

protons are the only part of an atom which has to stay same for it to be the same element .

Explanation:

I know because I looked the answer up so

here you go.

a, b, c - sides of a triangle

a + b > c

a + c > b

b + c > a

we have a = 5m and b = 11m. substitute:

5 + 11 > c

16 > c → c < 16

5 + c > 11         subtract 5 from both sides

c > 6

11 + c > 5         subtract 11 from both sides

c > -6

c < 16 and c > 6 and c > -6

thereofre your answer is 6m < c < 16m

no way! i don't want to spend my night being sick!