Chemistry > Periodic Table > 2.0 Modern Periodic Law & Modern Periodic Table
Periodic Table
1.0 Introduction
2.0 Modern Periodic Law & Modern Periodic Table
3.0 s,p,d,f Block Elements
4.0 Size and type of bonding in atoms.
5.0 Ionization Potential
5.1 Factor Affecting Ionization Potential
5.2 Trends in Ionization Potential
5.3 Ionization Potential of Transition Elements
5.4 Application of Ionization Potential
6.0 Electron Affinity
7.0 Electronegativity
2.1 Modern Periodic Table
5.2 Trends in Ionization Potential
5.3 Ionization Potential of Transition Elements
5.4 Application of Ionization Potential
- On the basis of the modern periodic law, a scientist name Bohr proposed a long form of periodic table that was prepared by Rang and Warner.
- In the periodic table the horizontal lines are periods and the vertical lines are groups.
- The periodic table has a total of 7 periods and 18 groups. But according to CAS system, the number of group is 16 because the 8th group has been divided into 3 groups.
- There are 2 elements in 1st period, 8 elements in each of the 2nd & 3rd periods, 18 elements in each of the 4th & 5th period, 32 elements in the 6th period and only 9 elements till now in the 7th period. Total 105 elements have been discovered so far.
- The 1st period is very short period, 2nd & 3rd are short periods, 4th & 5th are long periods, 6th is very long period while the seventh is incomplete period.
- The lanthanides (Elements from atomic number 58 to 71) and actinides (elements from atomic numbers 90 to 103) are included in the 6th & 7th periods, though these have been kept outside the periodic table.
Period | Atomic Number | Number of Elements | Remarks | |
From | To | |||
First (1st) | H, 1 | He, 2 | 2 | |
Second (2nd) | Li, 3 | Ne, 10 | 8 | |
Third (3rd) | Na, 11 | Ar, 18 | 8 | |
Fourth (4th) | K, 19 | Kr, 36 | 18 | |
Fifth (5th) | Rb, 37 | Xe, 54 | 18 | |
Sixth (6th) | Cs, 55 | Rn, 86 | 32 | including lanthanides |
Seventh (7th) | Fr, 87 | Ha, 105 | 19 | including actinides |
- Group: The modern periodic table has 18 vertical columns and according to CAS system there are 16 groups having the following number of elements.
S. No. | Group | Elements | ||
Number | Name | Family | ||
1 | 1 A | 7 | H, Li, Na, K, Rb, Cs, Fr | Alkali metals |
2 | II A | 6 | Be, Mg, Ca, Sr, Ba, Ra | Alkaline earth metals |
3 | III A | 5 | B, Al, Ga, In, Tl | Boron family |
4 | IV A | 5 | C, Si, Ge, Sn, Pb | Carbon family |
5 | V A | 5 | N, P, As, Sb, Bi | Nitrogen family |
6 | VI A | 5 | O, S, Se, Te, Po | Oxygen family / chalcogen |
7 | VII A | 5 | F, Cl, Br, I, At | Halogen family |
8 | Zero | 6 | He, Ne Ar, Kr, Xe, Rn | Inert elements |
9 | III B | 32 | Sc, Y, La, Ac 14 lanthanide elememts 14 actinide elememts | These elements of III B group, which could not be accommodated in one column. Therefore they are written separately outside the periodic table. |
10 | IV B | 4 | Ti, Zr, Hf, Ku | |
11 | V B | 4 | V, Nb, Ta, Ha | |
12 | VI B | 3 | Cr, Mo, W | |
13 | VII B | 3 | Mn, Tc, Re | |
14 | VIII (3) | 9 | Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt | |
15 | I B | 3 | Cu, Ag, Au | |
16 | II B | 3 | Zn, Cd, Hg | |
