The correct answer is:
Metals
They are all alkali and transition metals
Explanation:
The periodic table includes elements clustered into groups with comparable properties. Alkali metals are reactive, soft metals with low densities. Transition metals are unreactive metals that have many have common uses. Halogens are reactive non-metals that form glowing vapors.
If new evidence or observations falsify a scientific theory, the theory will have to be changed to adapt to the new data or just discarded altogether.
<span>Persamaan setara pada reaksi besi dengan asam klorida membentuk besi (II) klorida dan gas hidrogen
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Answer: 
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
Thus in the reactants, there are 2 atoms of hydrogen and 2 atoms of iodine .Thus there has to be 2 atoms of hydrogen and 2 atoms of iodine in the product as well. Thus a coefficient of 2 is placed in front of HI.
The balanced chemical reaction is:
