Metal An element that gives up electrons

Metal an element that gives up electrons relatively easily and is lustrous, malleable, and a good conductor of heat and electricity. (2.8)... 

Metal an element that gives up electrons relatively easily and is lustrous, malleable, and a good conductor of heat and electricity. (2.7) Metalloids (semimetals) elements along the division line in the periodic table between metals and nonmetals. These elements exhibit both metallic and nonmetallic properties. (7.13 19.1)... 

Metal An element that easily conducts heat and electricity, has high boiling and melting temperatures, and tends to give up electrons in chemical reactions. 

The derivation of the Debye-Hiickel equations is not included here, but only the end results. A complete discussion is given by Bull (1964), Chapter 3. There are, however, several basic phenomena that we need to examine. There are three mechanisms which produce ions in water solutions. These are (1) solution of an ionic crystal, (2) oxidation of a metal or reduction of a nonmetal, and (3) ionization of a neutral molecule. Most metals when they ionize give up electrons to an electronegative element so that both acquire the electronic structure of a rare gas. Exceptions of interest in electrode work are iron, copper, silver, mercury, and zinc. In the ionized state, these metals do not acquire the completed outer shell structure of a rare gas and do have residual valences. They are then somewhat unstable and complex with various molecules more easily than do the stable ionized metals with completed shells. This accounts for the poisoning of silver-silver chloride electrodes and p02-measuring electrodes when used in high-protein environments such as blood. 

The chemical elements provide examples of three of the four classes of crystalline solids described in this section. Only ionic solids are excluded, because a single element cannot have the two types of atoms of different electronegativities needed to form an ionic material. We have already discussed some of the structures formed by metallic elements, which are sufficiently electropositive that their atoms readily give up electrons to form the electron sea of metallic bonding. The nonmetallic elements are more complex in their structures, reflecting a competition between intermolecular and intramolecular bonding and producing molecular or covalent solids with varied properties. 

Along with the increase in the number of electrons comes an increase in the number of protons in the atoms nuclei. The increase in the magnitude of positive electrical charge in the nucleus increases the electrostatic force of attraction the nucleus exerts on all of an atom s electrons, with the result that atoms tend to decrease in size as one moves across a row of the periodic table from left to right. Thus, the atoms of nonmetallic elements tend to be much smaller than the atoms of metallic elements, with helium atoms being the smallest atoms of all elements. One consequence of the smaller size is that nonmetals have little tendency to give up electrons, so that nonmetals do not conduct electricity. 

There are general reactivity trends on the periodic table that are useful to know. Metals and nonmetals usually combine to form ionic compounds with the metal giving up an electron to become positively charged and the nonmetal element gaining an electron to become... 

Atoms of elements with widely different electronegativities tend to form ionic bonds (such as those that exist in NaCl and CaO compounds) with each other since the atom of the less electronegative element gives up its electron(s) to the atom of the more electronegative element. An ionic bond generally joins an atom of a metallic element and an atom of a nonmetallic element. Atoms of elements with comparable electronegativities tend to form polar covalent bonds with each other because the shift in... 

It is important to understand that simply being classified as a metal does not mean that an element behaves exactly like all other metals. For example, some metals can lose one or more electrons much more easily than others. In particular, cesium can give up its outermost electron (a 6s electron) more easily than can lithium (a 2s electron). In fact, for fhe alkali mefals (Group 1) the ease of giving up an election varies as follows ... 

The toxicity of an element such as sulfur is dependent on the presence, in the valency shell of the toxic element, of free electron pairs which are evidently necessary for the formation of the link with the catalyst. The toxicity—i.e., the power of forming a relatively strong chemisorptive bond—disappears if the structure of the molecule is of a shielded type in which this element is already associated with a completely shared electron octet. Thus, it appears (Maxted, 8) that the chemical bond by means of which the poison is linked to the metallic surface resembles the ordinary dative bond in which the poison is the donor. In the case of methyl sulhde adsorbed on palladium, indications have been obtained (Dilke, Eley, and Maxted, 9) by means of magnetic susceptibility measurements that electrons from the methyl sulfide enter the d-band of the adsorbing metal to give a coordinate link, the process being probably accompanied (Maxted, 10) by a filling up of the fractional deficiencies or holes in the d-band of the metal due to d- -band overlap which seem to be responmble for the catalytic activity of the transition metals (11). 

---