Which atom would tend to gain one valence from another atom in orther to become stable

Fluorine and sodium

Explanation:

Fluorine has 2,7 remaining one valance electron to be balance and sodium has 2,9 in which it will lose one too for both of them to be balanced so fluorine atom will receive 1 valence electron from sodium atom so they can both be balanced

heat the gas and measure the pressure

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west