Contrary to popular belief the scientific method is an iterative process because scientists often have to revisit, repeat or revise previous steps. It is very common for an experiment to be done many times in different international laboratories in order to confirm that a conclusion is valid. All good scientific experiments should allow results to be replicated.
Metals :-
Group 1A - Alkali metals ( highly reactive metals)
Non-metals :-
Group 17 - Halogens ( highly reactive non-metals )
Aluminum is the element that has an atom in the ground state with a total of three valence electrons
It's known as chromium (III) sulphate which is green in colour.
CH4 is the molecular formula for methane.