3) Two atoms have identical electron configurations. Which statement about the atoms is true?
a) They have the same chemical properties.
b) They must have the same mass.
c) They must have the same number of neutrons.
d) They could be atoms of different elements in the same group.

Write a paragraph that provides examples of each stage of volcanic activity, a description of the volcano, and facts about each stage.

What forms when chemical reactions combine pollution with sunlight?

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н,о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.