Question

Valency of elements first increases till group 14 and then decreases across a period in the Modern Periodic Table .
True or false ?

Answer 1

Answer:

On moving from left to right in a period, the chemical reactivity of elements first decreases and then increases. On moving from left to right in a period, the number of valence electrons increases from 1 to 8. On moving from left to right in a period, the atomic size decreases; the size of the atoms decreases. Since the atomic size decrease when we move from left to right in a period, therefore, electronegativity increases in moving left to right. Atomic size increases when moving down in a group thus electronegativity decreases when we move from top to bottom in the periodic table.  

Metallic character decreases as you move across a period in the periodic table from left to right. This occurs as atoms more readily accept electrons to fill a valence shell than lose them to remove the unfilled shell.