How did quantum mechanics change our understanding of atoms? a. in quantum mechanics, electrons exist in a cloud-shaped area outside the nucleus. b. in quantum mechanics, photons exist in a cloud-shaped area outside the nucleus. c. in quantum mechanics, photons are a part of the nucleus along with electrons. d. in quantum mechanics, photons are a part of the nucleus along with protons.

The correct answer is option A.

Explanation:

Schrodinger proposed the mechanic model of atom in which he defined the location of electrons inside an atom by electron cloud in 3-d space. And in order to locate them he introduced the concept of quantum numbers.

Where as photons are the discrete  packet or bundle of energy related to electromagnetic radiations.

im not exactly sure but i think its b!

the answers would be

the first one and the second one