Please help, it's a task in science and I'm really bad at this subject.

Which element has the lowest electronegativity? calcium(ca) gallium(ga) selenium(se) bromine(br)

Which statement describes the phase change that occurs when dry ice is placed in an open container at room temperature?

Question 3(multiple choice worth 4 points) (04.04 lc) what does it mean when an element is reduced? it empties a valance shell, reducing its atomic radius. it gains electrons, reducing its overall charge. it increases electronegativity, reducing its ability to bond. it loses electrons, reducing its electron number.