Answer:
"The elements are arranged in seven horizontal rows,called periods or series,and 18 vertical columns,called Groups."
Explanation:
Risk*
Because when equilibrium is reached, the reaction is still occurring in both directions, it's just that rate(forward) =rate(reverse) so there is no net change in the concentrations of the reactants or products.
Answer:
3.2L
Explanation:
PV=nRT
since pressure and temperature are held constant we have V=nR
R is a constant also,
Thus; 
v1=1.5L , n1=3mol, n2=1.4mol

v2=
v2=3.2L
Answer:
Various limitations of Mendeleev's periodic table are:-
Position of hydrogen - he couldn't assign a correct position to hydrogen as it showed properties of both alkali and halogens .
Position of isotopes - he considered that the properties of elements are a function of their atomic masses. Hence isotopes of a same element couldn't be placed.
In the d-block , elements with lower atomic number were placed before higher atomic number.
Explanation: