The odor of a smelly shower drain can be eliminated by removing debris from the drain. Discarding the odor-causing material in the garbage outside the home ensures the smell does not invade other areas. Boiling water dissolves oils and grease deposited on the sides of the pipe in the drain, which add to the smell.
Luckily for us, Nernst derived an equation that allows us to determine at what point the two forces (chemical and electrical gradients) balance each other - in other words, at what point we have an ionic equilibrium.
The most important factor to how atoms interact with their surroundings is the number of valence electrons they have. Elements in the same column of the table have the same number of valence electrons, so they react in similar ways. Backtracking to explain valence electrons: because of quantum mechanics, electrons can only fit in certain fixed states around a nucleus (the protons and neutron bundle that forms the core of every atom).