Answer:
All elements in the same group of the periodic table have the same number of valence electrons. This made it possible to compare the valence of the alien elements to the valence of elements from our periodic table, and match the alien elements to the correct group. For example, our group 14 elements all have 4 valence electrons, so the alien element with 4 valence electrons had to be part of group 14 also.
A chemical substance has the characteristics that it cannot be separated by physical methods. Seawater and milk can be separated by sedimentation, and air has different components depending on other aspects (such as elevation). Only ammonia is a substance. (thus it can have a formula: NH<span>3)</span>
D. It gives the same results when experiments are repeated
Lo afect porque cuando la temperature aumenta, el volumen aumentará, luego, cuando we mantiene la presión, es constante. Calentar el gas aumenta la emergía cinética we law partículas, lo que have que el gas se expanda.
Espero que esto ayude :)
