The product of two consecutive room numbers is 420. find the room numbers.

Step-by-step explanation:

Let the first number is x and other number is (x+1). The product of two consecutive room numbers is 420.

So, according to question,

On solving the above quadratic equation, we get the value of x as:

x = 20

and

(x+1) = 21

So, two numbers are 20 and 21.

4

step-by-step explanation:

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.