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1. One atom contains 29 protons and 34 neutrons. Another atom of the same element has a mass number of 65. How many protons and neutrons does this unknown atom have?

A. 28 protons, 37 neutrons
b. 29 protons, 36 neutrons
C. 29 protons, 35 neutrons
D. 31 protons, 34 neutrons

Respuesta :

Answer:

b

Explanation:

because its the atom of the same element, the no of protons doesn't change but the mass number changes so we can find the mass number by:

(mass number = atomic no/no of protons + no of neutrons)

here;

mass number given = 65

and we know, no of protons = 29

let no of neutrons = x

hence,

65 = 29 + x

x= 65 – 29

x= 36

hence your answer is b