Question

How is Oxygen -18 different from oxygen -16?

Answer 1

A  O-18 has 2 more neutrons than O-16

Further explanation

Oxygen is located in group 16 in the p block which has the atomic number 8

In the atomic symbol (neutral), the atomic number indicates the number of electrons and protons. while the number of neutrons is obtained from the difference between the mass number and the atomic number.

The isotope will have the same number of protons (atomic number) but a different mass number

Isotopes of oxygen include: O-18 and O-16

$\tt _8^{18}O~\rightarrow neutron=18-8=10,proton=8\\\\_8^{16}O\rightarrow neutron=16-8=8,proton=8$