Define valency. How does it change across a period and on going down a group?

Why does the ionisation energy decrease on going down a group?

State how density and melting points of elements varies across a period and down a group.

Give reason Atomic size decreases across a period but increases down a group of the periodic table

What type of oxides are formed by group 13 elements and how does their acidic character vary on moving down the group ?

In the periodic table, going down in fluorine group

State the general trend in periodicity in properties of oxides, hydroxides, oxy-acids and hydrides of compounds of elements across a period and down a group.

The electron affinity increases in going down a group.

Which of the following is generally true. A: Atomic size increases from left to right across a period. B: Ionization potential increases from left to right across a period. C: Electron affinity increases on going down a group. D: Electronegativity increases on going down a group.

Assertion:The atomic size generally increases across a period and decreases down the group. Reason:Atomic size depends upon valence shell electronic configuration.

Define group and period.