If an atom can form more than one cation, the cation with the lowest charge ends with which set of letters?
a. -ic b. -ide c. -ate d. -ous

Answer is A 

Explanation:

Now we know that an atom wants to complete its outer shell while keeping electrons in pairs of two now in A there are four electrons which which can be ejected while in B will want to accept 3 electrons to complete its shell as ejecting five will take lot of energy similar case will be for C,D and E which would want to accept 2,1,0 electrons respectively

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.