300×175 Express your answer using the correct number of significant figures.

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

State one important difference between a physical change and a chemical change?

Which of these describes how heat is transferred by convection* a. sunlight travels through space without the aid of fluids or solids. b. warm air rises and takes the heat with it, eventually, it cools and sinks c. air at the equator rises and sinks at the poles. d. air molecules touch the warm ground, heating them up *not conduction