Atomic radius

[shygurl475]

I'm really confused about something. I don't understand why the atomic radius decreases left to right on the periodic table if the atom doesn't get bigger. Can someone please explain this to me. So i was told that the atomic radius is the distance from the nucleus to the outer shell but since everything is the same when you go from left to right i don't get it.

[swansont]

What do you mean by "everything is the same when you go from left to right?"

[shygurl475]

What do you mean by "everything is the same when you go from left to right?"

 

well I mean that the element or whatever doesn't get bigger or smaller so how can the radius decrease?

[insane_alien]

elements to the right have a greater charge in the nucleus this holds the electrons tighter and hence, the elements have a smaller radius.

[Mr Skeptic]

All that the elements "want" from life is to complete their electron shell (so that they look like a noble gas). The closer an element is to the noble gasses from the left (the halogens) the higher the electronegativity, and the farther from the left, the less electronegativity (the alkali metals). This also will help you to understand bonding. Usually, this bonding is sharing pairs of electrons, increasing the effective number of both, but in the more extreme cases (those elements which are just right of the noble gasses mixing with those just to the left of the noble gasses), you can get ionic bonds where one element completely takes away an electron from the other element. I'm not a chemist, so take what I say with a grain of NaCl.

[swansont]

well I mean that the element or whatever doesn't get bigger or smaller so how can the radius decrease?

 

They do get smaller, though, as you go to the right on the periodic table.

[Cap'n Refsmmat]

As insane_alien said, elements on the right of the periodic table have more valence electrons and more protons to help pull the valence electrons in. This makes the elements slightly smaller.