Siven an element's atomic number and mass number, how can you tell the number of protons and neutrons in its nucleus?
jumber of protons = atomic number; number of neutrons = mass number - atomic number
number of protons = atomic number; number of neutrons = mass number + atomic number
number of protons = mass number; number of neutrons = atomic number - mass number

Number of protons = atomic number; number of neutrons = mass number - atomic number  

Explanation:

  Z = atomic number = number of protons

    A = mass number = number of protons + number of neutrons

          Mass number = atomic number + number of neutrons

Number of neutrons = mass number - atomic number

i guess that visual aids present persuasive examples to what you are presenting, some factors would be theme (does it fit with the color, information, what you are presenting), size (can you see it, is it a big enough span of data/information), and overall look of the visual aid.

hope this : )

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.