On the first math exam, 16 students received an A grade. On the second math exam,
12 students received an A grade. What percentage decrease is that?

A 75% decrease

Step-by-step explanation:

You set up a ratio table.

16 is 100%

12 is with an unknown percent so classified as x, since your cross multiplying, your multiplying 16 with x and 12 with 100.

You get 16x/16 = 1200/16

The two 16 cross each other out and your left with x so x is equal to 75

Thus 75%

 A 75 decrease.

Step-by-step explanation:

The person above me is correct.

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.