Por que los elementos del grupo 17 captan un electron con mucha facilidad, fomando un ion de carga -1, pero es muy dificil que capture un segundo electron y nunca forman iones con carga -2

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

i think its 100

i hope this !