Give the trend for atomic radius across a period and down a group, and explain each of these trends in terms of attraction, repulsion, and effective nuclear charge.

Atomic radius decreases across a period due to increase in attraction between nucleus & electrons in the valence shell, thus increasing effective nucleus charge.

Atomic radius increases down the group due to addition of one shell at each successive step

Hope this helps!

Answer Link

IlaMends IlaMends · Answer 2 · 2018-11-05T04:06:11-05:00

Explanation:

In a periodic table when we move down the group atomic radius increases .This is because:

On moving down the group new shells or energy levels are added to an atom.
By the addition of new shells valence electrons of the element gets far away from the nucleus.
As electrons are far way from the nucleus they will experience less attraction towards nucleus, less effective nuclear charge
Due to increase in size less electronic repulsion will be present between the electrons .

In a periodic table when we move across the period atomic radius decreases .This is because:

On moving left to right the shell or energy level remains the same.
The new electron enters in the same shell with increase in nuclear charge by one unit.
By this, more force of attraction and more effective nuclear charge is experienced by the electrons with high electronic repulsion among them selves.