Which of the following statements is true? Elements in the same period have similar properties.
Elements in the same group have the same number of electron shells.
The periodic table lists elements in ascending order of atomic numbers.
A molecule must be made of two or more different elements.

In vapor-liquid equilibrium in a binary mixture, both components are generally present in both phases. how many degrees of freedom are there for such a system? the reaction between nitrogen and hydrogen to form ammonia occurs in the gas phase. how many degrees of freedom are there for this system? steam and coal react at high temperatures to form hydrogen, carbon monoxide, carbon dioxide, and methane. the following reactions have been suggested as being involved in the chemical transformation: