Nonmetal atomic size

A common feature of metal atoms is that they are generally larger in size in comparison with nonmetal atoms. A characteristic of nonmetals is that their atoms have the ability to attach electrons to themselves, leading to the formation of anions. The opposite is true for the metals and as told they alter to cationic forms when their removable electrons leave them. 

Thus, for both metals and nonmetals, the atomic size increases as the atomic mass (weight) and atomic number increase. 

Because the additional electrons must be accommodated in valence orbitals, only nonmetal atoms in Period 3 or higher can expand their octets. These elements have empty ci-orbitals in the valence shell. Another factor—possibly the main factor—in determining whether more atoms than allowed by the octet rule can bond to a central atom is the size of that atom. A P atom is big enough for up to six Cl atoms to fit comfortably around it, and PC1S is a common laboratory chemical. An N atom, though, is too small, and NC15 is unknown. 

The group 4A elements exemplify the increase in metallic character down a group in the periodic table Carbon is a nonmetal silicon and germanium are semimetals and tin and lead are metals. The usual periodic trends in atomic size, ionization energy, and electronegativity are evident in the data of Table 19.4. 

It has already been emphasized that within a family of non transition elements, metallic character increases with increase in atomic number, atomic weight, and atomic size. There is no better illustration of this trend than Periodic Group Vb the lightest members of the group, nitrogen (Z = 7), and phosphorus (Z — 15), are typical nonmetals, whereas the heaviest member, bismuth (Z = 83) is a typical metal. The remaining members, arsenic (Z = 33) and antimony (Z 51) are intermediate in character and are often appropriately called metalloids. 

Figure 8.8 shows two common definitions of atomic size. The metallic radius is one-half the distance between nuclei of adjacent atoms in a crystal of the element we typically use this definition for metals. For elements commonly occurring as molecules, mostly nonmetals, we define atomic size by the covalent radius, one-half the distance between nuclei of identical covalently bonded atoms. 

Metallic behavior correlates with large atomic size and low ionization energy. Thus, metallic behavior increases down a group and decreases across a period. Within the main groups, metal oxides are basic and nonmetal oxides acidic. Thus, oxides become... 

How does the atomic size of a nonmetal affect the acidity of its binary hydride ... 

Metals Nonmetals Metalloids Atomic size Ionization energy... 

The atoms of nonmetals tend to be smaller than those of metals. Several of the other properties of nonmetals result from their atomic sizes. 

Metal oxides are ionic and act as bases in water, nonmetal oxides are covalent and act as acids in water. 8.48 Metallic character increases down a group and decreases toward the right across a period. These trends are the same as those for atomic size and opposite those for ionization energy. 8.52(a) Rb (b) Ra (c) I... 

Recall how a nonmetal atom such as chlorine changes to form a negatively charged ion. How do you think the size of a non-metal atom and a negatively charged ion of the same nonmetal will compare ... 

The small size of the hydrogen atom allows the unshared pair of an F, O, or N atom of one molecule to approach the H atom in another very closely. It is significant that hydrogen bonding occurs only with these three nonmetals, all of which have small atomic radii. 

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