posted by Anonymous .
Oxygen reacts 1:2 with sodium and is a colourless gas; chlorine reacts 1:1 with sodium and is a yellow gas; neon does not reacts with sodium and is a colourless gas. Suppose that a new element , pretendium, has been dicovered, and it is noted that this element reacts 1:1 with sodium and is bright green as a gas.
A) which chemical family would it belong to?
-I think halogens.
B) How many electrons would it have in its outermost shell?