Our understanding of the atom has changed over time. which idea that was once accepted is now considered scientifically inaccurate? a. the nucleus is the center of the atom. b. an atom is solid material. c. electrons have a negative charge. d. electrons are arranged in layers.

my sis just took the test the answer is

B.) An atom is solid material.

or An atom is a solid sphere.

The correct answer to the question is : B) An atom is a solid material.

EXPLANATION:

From Rutherford's alpha ray scattering experiment, we know that most of the spaces in an atom is empty.

It is so because most of the alpha particles in that scattering experiment had gone undeviated without any deflection by the positively charged nucleus.

Hence, atom can not be considered as a compact solid sphere.

conservation of mass

mass before something happens = mass afterwards

elctricity and magnet is conversion to it