Answer:
In chemical bonding: Arrangement of the elements. The horizontal rows of the periodic table are called periods. Each period corresponds to the successive occupation of the orbitals in a valence shell of the atom, with the long periods corresponding to the occupation of the orbitals of a d subshell.
Explanation:
The answer is A
According to research I have done, pure solids and liquids are not included in the equilibrium constant expression. If the concentration of a reactant in aqueous solution is increased, the position of equilibrium will move in the direction which minimises the effect of this increase in concentration, by using the added component up, to decrese it's concentration again.