Arrange these atoms and ions in order of decreasing size: Mg2+, Ca2+, and Ca. Now between F and F-: F- has one more electron, which causes the radius to be bigger. Sample Exercise 7.3 Atomic and Ionic Radii. We know that F and F- are both smaller than the rest because they have less shells. It is the fifth most abundant element on earth. It is a soft, silvery-white alkaline earth metal, whose name comes from the Latin word calx, which means lime. But since Te has one shell more than Rb+ is it bigger. Calcium (Ca) is a chemical element of the periodic table, located in the group 2 and the period 4, and is having the atomic number 20. We know that Te is smaller that Rb because of the trend of decreasing radius to the right within a period. Another reasoning is that since Rb+ has the same number of protons but less electrons, the electrons are held more tightly in Rb+. We know that Rb+ is smaller than Rb because it loses an electron and has one less shell. Rb and Te are in period 5, and F is in period 2. List the following species in order of increasing size: Rb, Rb+, F, F-, Te.įirst look in which periods the element is located. K+ and Ca 2+įor isoelectronic cations, the more positive the ionic charge, the smaller the ionic radius.įor isoelectronic anions, the more negative the ionic charge, the larger the ionic radius. This creates a larger negative charge in the electron cloud than positive charge in the nucleus, causing the electron cloud to 'puff out' a little bit as an ion.Ĭations (or anions) of different elements are said to be **isoelectronic** if they both have the same electronic configuration e.g.
When an atom gains one or more electrons, forming an anion, the added. For b) 'S'(2-) has a larger radius than the neutral S atom. This is because the loss of electrons reduces the shielding effect between the electrons and the nucleus, so the attraction of the nucleus for the electrons is greater, reducing the radius.
ion will thus has a larger atomic radius than argon, a potassium ion, or a calcium ion. For a) the neutral Ca atom has a larger radius than the 'Ca'(2+) ion. Why? Generally, non-metals gain electrons to achieve the octet. Which of the following atoms has the largest atomic radius.
Non-metals - the atomic radius of a non-metal is generally smaller than the ionic radius of the same element. This creates a larger positive charge in the nucleus than the negative charge in the electron cloud, causing the electron cloud to be drawn a little closer to the nucleus as an ion. Why? Generally, metals loose electrons to achieve the octet. Metals - the atomic radius of a metal is generally larger than the ionic radius of the same element. This article is part of the ChemHelp Tutoring Wiki
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