Periodic Table & Periodic Trends Flashcards
(48 cards)
Modern Periodic Law
“Physical & Chemical properties of elements are periodic functions of their atomic number.”
Moseley Contribution to the Periodic Table
He arranged elements in the order of increasing atomic number as the properties of elements depend on their electronic configuration.
Number of Periods
7
Number of Groups
18
Define: Periodicity
Occurrence of characteristic properties of elements at definite intervals in the modern periodic table when elements are arranged in increasing order of their atomic numbers.
Normal Elements Group Number
1 & 2, 13 to 17
Transition Elements Group Number
3 to 12
Noble or Inert Gases Group Number
18
Reactive Elements Group Number
1 & 2
Number of Elements in each period
2, 8, 8, 18, 18, 32, 26
Bridge Elements
ELements in Period 2 show similar properties to the elements diagonal to them in Period 3.
Other name for electropositive nature:
Metallic Nature
Other name for electronegative nature:
Non-Metallic Nature
Define: Electropositive/ Metallic Nature
Property of an element to lose electrons.
Define: Electronegative/ Non-Metallic Nature
Property of an element to gain electrons.
Define: Electron Affinity
It is the amount of energy released when an atom in the gaseous state accepts an electron to form an anion.
Define: Atomic Radius
It is the distance between the centre of the nucleus and the outer most shell of the atom.
Define: Ionisation Potential
It is the amount of energy required to to remove an electron from the outer most shell of an isolated gaseous atom.
Define: Electronegativity
It is the tendency of an atom to attract electrons to itself when combined in a compound.
Metallic nature __________ across a period from left to right.
decreases
Non-metallic nature __________ across a period from left to right.
increases
Metallic nature __________ down a group.
increases
Non-metallic nature __________ down a group.
decreases
Element with highest metallic nature :
Caesium(natural), Francium(man-made)
