Question

state, in terms of neutrons, why oxygen - 18 has a greater mass than oxygen - 16. it has a greater mass because

Explanation:

Oxygen - 16 and oxygen - 18 are isotopes of oxygen. Isotopes have the same number of protons (for oxygen, the atomic number \(Z = 8\), so \(p=8\)). The mass number \(A\) is given by \(A=p + n\) (where \(n\) is the number of neutrons). For oxygen - 16, \(A = 16\), so \(n=A - p=16 - 8 = 8\). For oxygen - 18, \(A = 18\), so \(n=A - p=18 - 8 = 10\). Since the mass of a neutron is non - zero (\(m_n\approx1.008665\ u\)), and oxygen - 18 has more neutrons (\(n = 10\)) than oxygen - 16 (\(n = 8\)), it has a greater mass.

Answer:

It has more neutrons.