Why is there a greater variety of compounds than of elements and atoms

What is the wavelength of a 3*10^12 hz infrared wave a 3*10^20m b 1* 10^4m c 3*10^-3m d 1*10^-4 m

How many neutrons does an element have if its atomic number is 50 and its mass number is 166

In a chemical reaction, the final amount of the products is determined by the a. universal gas law b. law of definite proportions c. air pressure d. temperature e. none of the above me