Chemistry
State the following
(i) Physical properties of elements which exhibit periodicity
(ii) Nature of hydroxides of elements which exhibit periodicity
Answer
(i) Physical properties of elements which exhibit periodicity are :
- Density
- Melting point
- Boiling point
Across a period — Density and melting point of elements increases gradually and then slightly decreases thereafter
Down a group — Density increases gradually, melting point and boiling point of elements decreases gradually
(ii) Nature of hydroxides of elements which exhibit periodicity is given below
- Across a period — The nature of hydroxides changes from strongly basic to amphoteric.
- Down a group — The nature of hydroxides changes from less basic to strongly basic, due to increasing atomic size and metallic character.
Related Questions
Complete the definitions of the periodic properties given below :
(a) Atomic size - the distance between — (b) Ionisation potential - the amount of energy required — (c) Electron affinity - the amount of energy released — (d) Electronegativity - the tendency of an atom to attract — (e) Metallic character - of an element is exhibited when an atom of the element loses — Complete the table of trends in periodic properties by -
(a) Filling in the blanks with 'decreases' or 'increases' across a period & down a group.
(b) The reasons for the 'decrease' or 'increase' based on the criteria given.
Trend Reason for trend Periodic property Across a period Down a group in periodic property (a) Atomic size No. of shells • Nuclear charge (b) Ionization potential Increases Atomic size • Nuclear charge (c) Electron affinity Atomic size • Nuclear charge (d) Electronegativity Decreases Atomic size • Nuclear charge (e) Metallic character Atomic size • Ionisation potential The alkali metal in period 2 and the halogen in period 3.
The noble gas having duplet arrangement of electrons.