Why do doctors and pharmacists take advantage of the fact that bacterium reproduces asexually​

Since asexual reproduction essentially makes clones of the parent bacterium, the daughter bacterium will behave and react exactly the same as the parent.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.