Identify the incorrect statement from the following options:

Explanation

Option A correctly defines isobars as atoms with the same total number of nucleons but different numbers of protons. Option B is incorrect because atoms with the same number of protons but different mass numbers are called isotopes, not isoters. Option C accurately states that gamma rays have the greatest penetration power among alpha, beta, and gamma radiation. Option D correctly explains that alpha emission decreases the mass number by four units.