Question

using the periodic table and your knowledge of atomic structure. cobalt (co) and nickel (ni) have almost identical atomic mass numbers. comparing the typical nickel and cobalt atoms, which statement best describes the atoms? a nickel has one more neutron. b cobalt has one less proton. c both atoms will have the same number of protons. d both atoms will have the same number of neutrons.

Explanation:

1. Recall that an element's atomic number equals its proton count. Cobalt (Co) has an atomic number of 27, so it has 27 protons. Nickel (Ni) has an atomic number of 28, so it has 28 protons. This means cobalt has one less proton than nickel.
2. Atomic mass number ≈ protons + neutrons. Cobalt's mass number is ~59, so its neutron count is $59 - 27 = 32$. Nickel's mass number is ~59, so its neutron count is $59 - 28 = 31$. This shows cobalt has one more neutron than nickel, eliminating options A and D. Option C is incorrect because the proton counts differ.

Answer:

B. Cobalt has one less proton.