Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.
Which elements have the smallest atomic radius?
Explanation: Helium has the smallest atomic radius.
Which of the following has smallest radius?
Hence, Cl has the smallest radius.
Does hydrogen have the smallest atomic radius?
Hydrogen (H) has the smallest average atomic radius at about 25 pm, while caesium (Cs) has the largest average radius at about 260 pm.
Which ion has the smallest radius?
For Na+: The atomic number of Na is 11. Na+ has a charge of +1 which means Na lost 1 electron. This means the number of electrons in Na+ is 11 – 1 = 10 electrons. This means Na+ will have the smallest radius since it has the least number of electrons.
Is Br or Br bigger?
Br – will have the largest atomic size because Br- has one extra electron in its valence shell which due to its unbalanced negative charge will be repelled and hence the atomic radius of Br- will increase.
Which elements have the highest atomic radius?
Explanation: Francium has the largest, Helium has the lowest. Atomic radius increases as you go to the left and downward due to the attraction of electrons and the nucleus in an atom.
Which cation has the smallest radius?
Note trends for ionic radii: ionic radius of a cation is less than atomic radius of the atom. ionic radius of an anion is greater than atomic radius of the atom.
…
Key Concepts.
| atomic radius decreases across a period from left to right | Li |
|---|---|
| Be | |
| B | |
| C | |
| N |
How do you find atomic radius?
Atomic radius is determined as the distance between the nuclei of two identical atoms bonded together. The atomic radius of atoms generally decreases from left to right across a period. The atomic radius of atoms generally increases from top to bottom within a group.
Which element has a larger atomic radius than phosphorus?
Atomic Radius of the elements
| Helium | 31 pm | 161 pm |
|---|---|---|
| Phosphorus | 98 pm | 183 pm |
| Selenium | 103 pm | 184 pm |
| Xenon | 108 pm | 185 pm |
| Silicon | 111 pm | 188 pm |
Why is K bigger than Br?
Since potassium is located at the start of period 3, and bromine at the end of the same period, potassium will have a larger atomic radius than bromine, and thus the largest atomic radius of the four given atoms.
Why does atomic radius increase from right to left?
This is caused by the increase in the number of protons and electrons across a period. One proton has a greater effect than one electron; thus, electrons are pulled towards the nucleus, resulting in a smaller radius. Atomic radius increases from top to bottom within a group. This is caused by electron shielding.
Why is the atomic radius of hydrogen smaller than potassium?
Across a period, atomic radius decreases from left to right. Explain why the atomic radius of hydrogen is so much smaller that the atomic radius for potassium. … K^+ is smaller in size than K because it has one less electron. Cl^- is larger than Cl because it has one additional electron.
Which ion has the largest atomic radius?
1 Answer. Ernest Z. K+ has the largest radius.
Which ion has largest size?
Consequently, the ion with the greatest nuclear charge (Al 3 +) is the smallest, and the ion with the smallest nuclear charge (N 3−) is the largest.
…
Ionic Radii and Isoelectronic Series.
| Ion | Radius (pm) | Atomic Number |
|---|---|---|
| N 3− | 146 | 7 |
| O 2− | 140 | 8 |
| F − | 133 | 9 |
| Na + | 98 | 11 |
Do you predict that the ionic radius of Sr2+ is larger or smaller in size than the ionic radius of Mg2+?
Hence, from the electronic configuration of Mg2+ ( [He]) and that of Sr2+ ([Kr]), the Sr^2+ ion is much larger and has many more intervening shells than Mg2+. Hence it follows that as we move down group 2, we expect that the ionic radius should increase in accordance with the reason given above.