Determine the number of protons and neutrons in each isotope.

(a)

(b)

(c)

(d)

Solution 97P

Step 1:

The isotopes of the same element have similar chemical behavior.

(a) In 1123Na the atomic number is 11, so there are 11 protons and 11 electrons. The mass number is 23, so there are 12 (=23-11) neutrons.

Step 2:

(b) In 88266Ra the atomic number is 88, so there are 88 protons and 88 electrons. The mass number is 266, so there are 178 (=266-88) neutrons.