9. Describe how elements form ions that have a stable atomic structure like that found in a noble gas. Give at least two examples.

chemists can use the electron cloud model to assign electrons to different atomic orbitals. atomic orbitals also explain the patterns in the periodic table

explanation:

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