Which element have a higher first ionization energy and electron affinity? Mg vs Al

15. which of the following is not human-caused groundwater pollution? a. water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock. b. water in an aquifer is contaminated by leachate that seeps into the ground from a landfill. c. water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking. d. water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.

What does a complete balanced chemical equation include? a. exothermic coefficients b. endothermic coefficients c. valence electrons d. molar coefficients

Which type of reaction involves the absorption of energy from the surroundings?