87) A
88) D
89) B
90) E
91) C
There is this thing called isotopes
it means that atoms of the same element can have a different number of neutrons.
if there is a change in the no. of neutrons, there will definitely be a change in the mass number.
so the answer is A) mass number
A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water. The neutralization of a strong acid and strong base has a pH equal to 7.
Since it is in period five, any element that has a higher atomic number than it could be an answer, therefore, silver, bismuth, and osmium are possibilities.
Answer:
Double replacement.
Explanation:
Chemical Reactions => Double Replacement Reactions.
Let's call Ted as T, Emily as E, Jack as J, and Brenda as B.
In the first match, we have T and E playing against J and B; and in the second match, we have T and B playing against J and E. We can state a 'reaction' of this if the first match would be the reactants and the second match the products:

You can note that this is similar to a double replacement reaction, remember that a double-replacement reaction is a reaction in which the positive and negative ions of two ionic compounds exchange places to form two new compounds. The general form of a double-replacement reaction is:

which is similar to the reaction of the game, so the answer would be Double replacement.