You divide first what operation would you use last 18(d/3-9)=198

addition

Step-by-step explanation:

18 ( d - 9 ) = 198

      3

divide both side by 18

d - 9 = 198  

3          18

d - 9 = 11

3

multiply both sides by 3

d - 27 = 33

add 27 to both sides

d = 33 + 27

lastly, add them together

d = 60

therefore, the last step is addition

college

the answer is: d) o, f, and kr.

atomic radius of bromine (br) is 114 pm.

atomic radius of oxygen (o) is 73 pm.

atomic radius of fluorine (f) is 72 pm.

atomic radius of krypron (kr) is 112 pm.

the atomic radius of a chemical element is a measure of the size of its atom.

the atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

the atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.