Arrange K, F, Ba, Pb, B, and I in order of decreasing atomic radius.

 Calculated Atomic Radii (in Picometers) of the -, -, and -Block Elements


Solution. (i) The species 0 has the smallest radius because the radius of anion is always larger than the radius of the atom from which it is formed. o- and o:z- are anions of oxygen.

Atomic radii of halogens - Modern and Theoretical …

(iii) Cl has the smallest radius. Si, P and Cl belong to same period. In a period atomic radius decreases with increase in atomic number due to increase in effective nuclear charge.

Covalent atomic radii can be determined for most of the nonmetals, but how do chemists obtain atomic radii for elements that do not form covalent bonds? For these elements, a variety of other methods have been developed. With a metal, for example, the is defined as half the distance between the nuclei of two adjacent metal atoms (part (b) in ). For elements such as the noble gases, most of which form no stable compounds, we can use what is called the , which is half the internuclear distance between two nonbonded atoms in the solid (part (c) in ). An atom such as chlorine has both a covalent radius (the distance between the two atoms in a Cl2 molecule) and a van der Waals radius (the distance between two Cl atoms in different molecules in, for example, Cl2(s) at low temperatures). These radii are generally not the same (part (d) in ).

Applications of STEM-EELS to complex oxides - …

(a) The internuclear distance is apportioned between adjacent cations and anions in the ionic structure, as shown here for Na+ and Cl in sodium chloride. (b) This depiction of electron density contours for a single plane of atoms in the NaCl structure shows how the lines connect points of equal electron density. Note the relative sizes of the electron density contour lines around Cl and Na+.

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The radius of anion is larger than that of parent atom. Anion is formed by the gain of one or more electrons by the gaseous atom. In the anion, the nuclear charge is the same as that in the parent atom but the number of electrons has increased. Since same nuclear charge now acts on increased number of electrons, the effective nuclear charge per electron decreases in the anion. The electron cloud is held less tightly by the nucleus. This causes increase in the size. The relative sizes of chlorine atom and chloride ion have been shown in Fig. 6.8.

Which of the entities have higher atomic radius

A comparison of ionic radii with atomic radii () shows that a . When one or more electrons is removed from a neutral atom, two things happen: (1) repulsions between electrons in the same principal shell decrease because fewer electrons are present, and (2) the effective nuclear charge felt by the remaining electrons increases because there are fewer electrons to shield one another from the nucleus. Consequently, the size of the region of space occupied by electrons decreases (compare Li at 167 pm with Li+ at 76 pm). If different numbers of electrons can be removed to produce ions with different charges, the ion with the greatest positive charge is the smallest (compare Fe2+ at 78 pm with Fe3+ at 64.5 pm). Conversely, adding one or more electrons to a neutral atom causes electron–electron repulsions to increase and the effective nuclear charge to decrease, so the size of the probability region increases (compare F at 42 pm with F at 133 pm).

in the trend of atomic radi along the ..

Source: Ionic radius data from R. D. Shannon, “Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides,” 32, no. 5 (1976): 751–767.