# Objective Chemistry (2 questions)

1. Dec 10, 2007

### ritwik06

1. The problem statement, all variables and given/known data

1. Why is the atomic size of 0 group elements more than that of the rest of the elements in that period?
2. Which is th element with least electron affinity?

2. Relevant equations

None

3. The attempt at a solution

1. Force of repulsion between the electrons is what my teacher tell me.
2. A noble gas or francium???

Help!

2. Dec 10, 2007

### ShawnD

Which group is 0? My table has 1-18 across and 1-7 down. I've never seen a table that starts at 0.

Two main things affect size - electronegativity and overall number of electrons. Fluorine is very small because of its high electronegativity and low number of electrons; it can tightly hold electrons close to the nucleus. Potassium is big because of its low electronegativity; electrons stay far from the nucleus and can be easily pulled away by things like fluorine or oxygen. Radon is big because it has 86 electrons.

Francium.

3. Dec 10, 2007

### Gokul43201

Staff Emeritus
Group 18 (noble gases) is sometimes refered to as group 0.

I've not actually seen a periodic table with this format. Does Group 0 actually get arranged to the left of group 1? In the more common version of the priodic table, group 18 elements have the smallest (not largest) atomic radii of all elements in a given period. But if you pushed that group to the left side and promoted every element to the next period, then the converse would be true.

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