B ia the correct one .
Hydrogen only uses the first energy shell, which holds 2 electrons, not 8.
<span>When a chemical reaction occurs and the thermometer in the container records a drop in temperature t</span>he reaction is exothermic because heat was released by the reaction.
<span>B. The reaction is exothermic because heat was released by the reaction. is your answer.
Hoped I helped!</span>
Answer:
Explanation:
Iso-electronic species have same number of electrons . Positive charged ions will have smaller size . As electrons add , size increases due to electronic repulsion .
Following species are isoelectronic .
Al³⁺ < Mg²⁺ < Na¹⁺ < Ne < F⁻¹ < O⁻² < N⁻³
B the girls arm will act as a pulley
