atomic radius

[halle young 4A]

why does the atomic radius decrease across the periodic table?

[Reagan Smith 1H]

It decreases across a period because the electrons are in the same orbital across a period but the number of protons increases across a period, so the pull from the positive nucleus on the negative electrons pulls the electrons closer, decreasing radius.

[Alice Chang 2H]

The trend is towards the bottom left is increasing atomic radius, right?

Basically the way that I think of it, on the top right of the periodic table, the elements have less electrons to shield the outer electrons, so the protons in the nucleus have a stronger pull. Meanwhile, on the bottom left, these elements have a large radius because they have more electrons to shield the outermost electrons from the proton's pull, therefore allowing for the outermost electrons to freely roam without much pull from the nucleus.

Hope this helps.

[ranqiao1e]

As effective nuclear charge decreases the electrons are held less closely together, so the atomic radius is larger.

[CynthiaLy4F]

Atomic radius decreases across the periodic table because the increased number of protons causes a greater effective nuclear charge that pulls electrons in, resulting in a smaller radius.

[Joelle 3L]

When you go across a period there are more protons in an element, making it have a greater effective nuclear charge. The electrons would be added to the same energy levels but since there are more protons going across a period the protons would have a tronger pull making the atomic radius smaller.

[Bradley Whitworth 4B]

Moving across a period the nucleus is gaining protons so there is much more positive charge pulling on the electrons meaning the radius becomes smaller.

[Megan Ngai- 3B]

It decreases across the periodic table because there are more protons so there’s a strong nuclear charge pull.