What are the drawbacks of Rutherford's model of atom?

How was neutron discovered?

What does the atomic number of an element tell about the element?

Write down the electronic configuration of the following:

Oxygen (Atomic number $=8$).

Write down the electronic configuration of the following:

Phosphorous (Atomic number $=15$).

Write down the electronic configuration of the following

Calcium (Atomic number$=20$)

Write down the electronic configuration of the following

Silicon (Atomic Number$=14$)

Give the nuclear structure and the distribution of electrons of the following element:

Nitrogen.