Predict the electronegativity of the yet undiscovered element with Z = 119.

We know that the element Z = 119 would be placed right below the Fr, in the column of the alcaline metals.

We also know that the trend in the electronegativity is to decrease when you go up-down ia group.

The known electronegativities of the elements of this group are:

Li: 0.98

Na: 0.93

K: 0.82

Rb: 0.82

Cs: 0.79

Fr: 0.70

Then the hypotetical element Z = 119 would probably have an electronegativity slightly below 0.70, for sure in the range 0.60 - 0.70.