Atom

• An atom is the basic unit of matter. It consists of a nucleus containing positively charged protons and uncharged neutrons, surrounded by negatively charged electrons that orbit the nucleus in shells.
  Atomic Theory is given by John Dalton

Quark:

• The smallest part of the atom is called a quark.
  Quark ‹ atom

Amedeo Avagadro

• Amedeo Avagadro’s Number = 6.022 x 10^23.  Avagadro’s Constant (N_A) = 6.0222 x 10²³ Mol^-1 
  01 Mol of Carbon (C-12) in gram=6.022 x 10²³
  C-12 i.e 12 gram= 6.022 x 10²³ or 0.12 gram= 6.022 x 10²¹ or 06 gram= ½. 6.022 x 10²³

Nucleus, Electron, Proton, Neutron:

• Nucleus: Discovered by Rutherford
• Electron: Discovered by JJ Thomson and got the Nobel Prize in 1906. The charge on an electron is -1.6022 x 10^-19 C and the Mass on an electron is 9.1 x10^-31 kg. Note: JJ Thomson also discovered the Mass Spectrometer, which measures the Mass of the smallest Particle.
• Proton: Discovered by Rutherford and got the Nobel Prize in 1908. The charge on a Proton is +1.6022 x 10^-19 C and the Mass on a proton is 1.67 x10^-27 kg. Note: Goldstein discovered the Canal Ray/Anode Ray and later the same Canal Ray/Anode Ray known as Proton
  A Canal Ray/Anode Ray is the ray of a proton and a Cathode Ray is the beam of an electron
• Neutron: Discovered by Chadwick and got the Nobel Prize in 1935. The charge on a neutron is zero and the Mass on a neutron is 1.674 x10^-27 kg.
• Positron (The Anti-Particle of Electron): Discovered by Anderson.
• Neutrino (The Chargeless and Massless Particle): Discovered by Pauli
  

1. Atomic Number = Number of electrons/ or number of Protons
2. Atomic Mass = Neutron + Proton [sum of both]
3. Formula to find out the total number of electrons in the n^th shell= 2 x n²
   

   

for example: K= 2 x 1¹ = 2, L= 2 x 2² = 8, M= 2 x 3² = 18, N= 2 x 4² = 32
where K, L M, N are the shells in which electrons revolve around the nucleus and s, p, d, f are the sub-shell of the K/L/M/N shell respectively. The number of electrons in the s, p, f, and d sub-shell are 2, 6, 10, and 14 respectively.
for example, Potassium (K)= 19

No of electrons in the L shell are 08, and for stability 01 electron goes to the N orbit of sub-shell (according to the Octate Rule given by Kossel and Lewis)

Isotopes, Isobar, Isotones:

1. Isotopes: Elements having the same number of protons (p) are called Isotopes.
   for example, C-12, C-13, C-14 have same number of Protons = 6
2. Isobars: Elements having the same number of atomic masses (p+n) are called Isobars.
   for example, N-14 and C-14 have same Atomic Mass = 14
3. Isotones: Elements having the same number of Neutrons (n) are called Isotones.

for example, C-13 and N-14 have same number of Neutrons = 7

1. Here C-12 = atomic number of carbon  is 12 and N-14= Nitrogen (atomic number 14)
2. C-14 is a Radioactive element, used in the Carbon Dating Method to estimate the age of fossils.
3. The uranium-lead method is used to estimate the life of Earth (life of Earth=3.5 billion years).
4. Due to the Low “Half-life period” Isotopes are used for the detection or Treatment of diseases.
   For example: a) Na-24: to detect Blood cancer
   b) P-32: Blood cancer in WBCs (WBCs normal life=8k-10k, cancer WBCs life=20k-40k  )
   c) Co-60: used in general cancer treatment
   d) I-131: For thyroid cancer
   e) Radium-223: For Bone cancer
   f) Arsenic-74: For Brain cancer

Proteium, Deutrium, Tritium

₁H³ the lightest Radioactive element, discovered by Rutherford, ₁H³ emits only β-Rays.

• In our earth’s atmosphere, the sequence of  availability of elements
  N₂(78%)> O₂(21%)>Argon(0.9%)> CO₂(0.03%)
  Among the inert gases, Argon is present maximum in the atmosphere.
• Hydrogen is more than Helium in the universe.

Atomic Model:

1. JJ Thomson Model: Also called Watermelon/Raisin/Plum-Pudding Model
2. Neils Bhor Model: Also called the Planetary Model.

Heavy Water Vs Normal Water:

• Heavy Water(D2O): (Note: Not Hard water) Molecular Mass=20μ (2*2+16*1=20)
  Discovered by Uray and Miler. Heavy water is used as a moderator in Nuclear reactions. The authorised centre for making heavy water in India is Bhabha Atomic Research Centre (Trombay-Mumbai-Maharastra).
• Normal Water(_H2O): Molecular Mass=18μ (1*2+16*1=18)