$522
20% of 358 of 69.6 so we add those together. Then, 25% of the sum is 522
Answer:
Krypton is a noble gas, so it was difficult for chemists to find it, as though it was a secret.
Explanation:
Krypton (₃₆Kr), an element with atomic number 36, belongs to group 18 on the periodic table of elements. This group is a specific one - it's made up of elements known as noble gases. Besides krypton, these elements are: helium, neon, argon, xenon, and radon. All noble gases were characterized relatively late compared to other elements. They all conduct electricity, fluoresce, and are odorless and colorless. Besides that, they have very low chemical reactivity. Because of their stability, they are often used to maintain a safe, constant environment. As krypton shares all of these characteristics, it was difficult for chemists to find it. That's why it was most likely given that name.
The word that best describes the tone of the excerpt is : ( C ) Methodical
<h3>What is methodical procedure ?</h3>
Methodical procedure describes the sequential procedure in which a system of actions is been followed usually computer systems or other forms as seen in the excerpt.
Hence we can conclude that the word that best describes the tone of the excerpt is methodical.
Learn more about methodical procedure : brainly.com/question/6947486
#SPJ1
<u>Attached below is the missing excerpt </u>
<em>I knew I could never let Mom hear the messages, because protecting her is one of my most important raisons d’être, so what I did was I took Dad’s emergency money from on top of his dresser, and I went to the Radio Shack on Amsterdam. It was on a TV there that I saw that the first building had fallen. I bought the exact same phone and ran home and recorded our greeting from the first phone onto it. I wrapped up the old phone in the scarf that Grandma was never able to finish because of my privacy, and I put that in a grocery bag, and I put that in a box, and I put that in another box, and I put that under a bunch of stuff in my closet, like my jewelry workbench and albums of foreign currencies. </em>
