Arrangement of the electrons

Question 1

History of an atom

Answer 1

• 1913: Niels Bohr had idea of tiny positive nucleus
  orbited by negatively charged electrons
• 1926: Erwin Schorodinger discovered quantum
  mechanics used to predict behaviour of sub
  atomic particles
• 1932: James Chadwick discovered the neutron

Question 2

How many electrons go in each shell?

Answer 2

First Shell = 2 electrons
Second Shell = 8 electrons
Third Shell = 18 electrons

Question 3

What is carbon in shorthand?

Answer 3

2,4