7. Experiments performed to reveal the structure of atoms led scientists to conclude that an atom's
A) positive charge is evenly distributed
throughout its volume
B) negative charge is mainly concentrated in its
nucleus
4) volume is mainly unoccupied
D) mass is evenly distributed throughout its
volume

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

the atomic mass is the bottom number on the element.

-steel jelly

the increase of protons   hope this

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.