Types of Atomic Species

 

1. Isotopes: (Iso = same, topos = place)

Ø  Atom of the same element having same atomic number but different mass number.

Ø  They have same chemical properties and different physical properties

Ø  They contain equal number of electron and same electron configuration for e.g. a.₁H¹, ₁H², ₁H³, b. ₁₇C¹³⁵, ₁₇c¹³⁷

Ø  Physical properties likes density, rate of diffusion etc. of isotopes are different because they depend upon the mass number

2. Isobars

Ø  Atoms of different element having same mass number but different atomic number

Ø  They have different chemical properties for e.g.
a. ₆c¹⁴, ₇N¹⁴
b. ₁₈Ar⁴⁰₁₉K⁴⁰, ₂₀Ca⁴⁰, etc.

3. Isotones

Ø  Atoms of different elements having the same number of neutrons e.g.
a. ₆C¹³, ₇N¹⁴
b. ₁H³, ₂He⁴, etc

4. Isosters

Ø  Species having same number of atoms and electron e.g.
a. HCl & F₂
b. N₂& CO
c. N₂O₄CO₂­, etc.

5. Isodiapheres

Ø  These are the atoms of same difference in number of protons and neutrons e.g.
a. ₉₂U²³⁵, ₉₀Th²³¹
b. ₂₉Cu⁶⁵, ₂₄Cr⁵⁴ etc.

6. Isomorphs

Ø  Identical crystal structure, similar constituent and chemical formulae for e.g. K₂SO₄, K₂CrO₄, (valance of S, Cr is 6)

7. Isoelectronic

Ø  Atoms or compounds having same no. of electron and electronic configuration for e.g.
a. N₂O, CO₂
b. H^-, He, Li⁺
c. N₂O, CO₂, etc.