What is an atom is made up of?

Describe the location of the subjects in an Atom?

How come the Electrons doesn't float away?

Describe how many electrons the first, second and third shell can hold?

Draw a diagram of an atom of:
Lithium

Draw a diagram of an atom of:
Beryllium

Draw a diagram of an atom of:
Boron

Write down following for Lithium:
The mass number
The proton number
The number of electrons, protons and neutrons

Write down following for Beryllium:
The mass number
The proton number
The number of electrons, protons and neutrons

Write down following for Boron:
The mass number
The proton number
The number of electrons, protons and neutrons