Will give out brainliest.. name the 2 elements that have the same number of valence electrons. name the elements that would be classified as metals. name the 2 elements that are in the same period. name the 2 elements that are in the same family. name the element that has the smallest atomic number. if the atomic number of element c is 20, then what is the atomic number of element d?

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 answer is b. dilution