Question

you will need to obtain a periodic table. tin is an example of an element that has a great number of naturally occurring isotopes. how many neutrons would be present in the isotope tin - 120?
a 69
b 66
c 68
d 70

Explanation:

Step1: Find tin's atomic number

From the periodic table, tin (Sn) has an atomic number of 50. Atomic number = number of protons.

Step2: Calculate number of neutrons

The mass - number of tin - 120 is 120. Mass number = number of protons + number of neutrons. So, number of neutrons = mass number - number of protons. Neutrons = 120 - 50 = 70.

Answer:

d. 70