If element X has 5 valence electrons, what would you expect it to do to fulfil its octet? pls help

Which of these conditions most likely produces an unstable isotope?

For each of the following compounds, write the formula then predict whether it would be a strong, weak, or non-electrolyte when placed in di water. for the ionic compounds only, put (s) or (aq) after the forrmula formula strong, weak or non electrolyte? a calcium hydroxide b. silver carbonate c. lead(ii) sulfate d. phosphorus trifluoride e. sodium phosphide f barium sulfate g. strontium acetate h. zinc nitrate

What woukd most likely be the transmittance at a 0.70 m solution of solute a? a) 7.6%b) 1.1%c)4.0%d)4.6%