Question

Which of these phrases best describes an atom?(1) a positive nucleus surrounded by a hard negative shell

(2) a positive nucleus surrounded by a cloud of negative charges
(3) a hard sphere with positive particles uniformly embedded
(4) a hard sphere with negative particles uniformly embedded

Answer 1

The best description of an atom is option (2), a positive nucleus surrounded by a cloud of negative charges; this refers to the central nucleus with protons and neutrons and the surrounding electron cloud.

Step-by-step explanation:

The correct description of an atom is a positive nucleus surrounded by a cloud of negative charges. This defines the modern view of atomic structure, which includes a central nucleus that contains protons with positive electric charge, and neutrons with no electric charge, all of which are packed tightly together. This nucleus carries nearly all the mass of the atom. Surrounding this nucleus is a diffuse cloud of electrons, which carry a net negative charge. This electron cloud occupies most of the volume of the atom but contains very little of its mass. Accordingly, the statement that best describes an atom from the given options is (2) a positive nucleus surrounded by a cloud of negative charges.

Answer 2

"(2) a positive nucleus surrounded by a cloud of negative charges" is by far the best option, since the "cloud" formation of electrons replaced the orbital model.