Which element when combined with fluorine would most likely form an ionic compound

Is 343 in the sequence -5, -2, 1, 4, 7

Which of the four hypothetical substances you investigated would be most harmful to living organisms? 50 points!

C=59(f−32)the equation above shows how temperature f, measured in degrees fahrenheit, relates to a temperature c, measured in degrees celsius. based on the equation, which of the following must be true? a temperature increase of 1 degree fahrenheit is equivalent to a temperature increase of 59 degree celsius.a temperature increase of 1 degree celsius is equivalent to a temperature increase of 1.8 degrees fahrenheit.a temperature increase of 59 degree fahrenheit is equivalent to a temperature increase of 1 degree celsius.a) i onlyb) ii onlyc) iii onlyd) i and ii only