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I need an answer now please asap and you will me marked brainiest please it's missing I need it now.

I need an answer now please asap and you will me marked brainiest please its missing I need it now class=

Respuesta :

Answer:

alll of them are possible, besides the last one

Explanation:

All of them are correct compounds besides the last one. The last one isn’t a correct compound because the second element does not exist

#NaO_2

  • Impossible
  • Na has valency 1 so O can never have 2 as subscript.

Correct compound=Na_2O

#MgCl_2

  • Possible
  • Valency of Mg is 2 and Cl is 1 so yes

#CaF

  • Impossible
  • Ca has valency 2 not 1

#NaBr

  • Possible
  • Na has valency 1 and Br has 1

#KHe

  • Impossible

Helium is a noble gas so can't form compounds