The reaction is endothermic because the temperature dropped from 28 degrees Celsius to 20 degrees Celsius.
<h2 /><h2>Meaning of endothermic and exothermic reaction:</h2>
An endothermic reaction is one in which heat is absorbed from the surrounding resulting in decrease in temperature while an exothermic reaction is one in which heat is evolved causing the temperature to rise.
In the particular context of this question, the reaction is endothermic because the temperature dropped from 28 degrees Celsius to 20 degrees Celsius. The heat in the surroundings decreased.
An atom is the smallest particle of matter that still retains the property of the element.
Two or more atoms combine to form elements or compounds. Elements are formed by two or more similar atoms, while compounds are formed by two or more different elements.
Atoms are made up of subatomic particles; protons, electrons and neutrons. Electrons are negatively charged, protons are positively charged while neutrons have no charge.
I think the correct answer is the first option. It has nonpolar bonds and a symmetrical structure. The structure of a BF3 molecule shows a symmetrical trigonal geometry. The net dipole moment of the molecule is zero therefore it is polar.