![]() ![]() Classify each element in Conceptual Problem 1 ( Section 1.Other important groupings of elements in the periodic table are the main group elements, the transition metals, the lanthanides, and the actinides. Metals are lustrous, good conductors of electricity, and readily shaped (they are ductile and malleable), whereas solid nonmetals are generally brittle and poor electrical conductors. They are separated by a diagonal band of semimetals. Metals are located on the left of the periodic table, and nonmetals are located on the upper right. Semimetals exhibit properties intermediate between those of metals and nonmetals. The elements can be broadly divided into metals, nonmetals, and semimetals. Some of the groups have widely used common names, including the alkali metals (group 1) and the alkaline earth metals (group 2) on the far left, and the halogens (group 17) and the noble gases (group 18) on the far right. Elements that exhibit similar chemistry appear in vertical columns called groups (numbered 1–18 from left to right) the seven horizontal rows are called periods. The periodic table is an arrangement of the elements in order of increasing atomic number. As expected, semimetals exhibit properties intermediate between metals and nonmetals. Most solid nonmetals are brittle, so they break into small pieces when hit with a hammer or pulled into a wire. Nonmetals can be gases (such as chlorine), liquids (such as bromine), or solids (such as iodine) at room temperature and pressure. Nonmetals, in contrast, are generally poor conductors of heat and electricity and are not lustrous. Of the metals, only mercury is a liquid at room temperature and pressure all the rest are solids. 7.2: Evidence of a Chemical Reaction 7.3: The Chemical Equation 7.4: How to Write Balanced Chemical Equations. The vast majority of the known elements are metals. 4.6: Looking for Patterns: The Periodic Law and the Periodic Table 4.7: Ions: Losing and Gaining Electrons 4.8: Isotopes: When the Number of Neutrons Varies 4.9: Atomic Mass: The Average Mass of an Element’s Atoms. Metals-such as copper or gold-are good conductors of electricity and heat they can be pulled into wires because they are ductile they can be hammered or pressed into thin sheets or foils because they are malleable and most have a shiny appearance, so they are lustrous. The distinction between metals and nonmetals is one of the most fundamental in chemistry. As you might expect, elements colored in gold that lie along the diagonal line exhibit properties intermediate between metals and nonmetals they are called semimetals. The heavy orange zigzag line running diagonally from the upper left to the lower right through groups 13–16 in divides the elements into metals (in blue, below and to the left of the line) and nonmetals (in bronze, above and to the right of the line). The semimetals lie along a diagonal line separating the metals and nonmetals. The metals are on the bottom left in the periodic table, and the nonmetals are at the top right. Ionization energy increases from moving left to right in period and decreases on moving down in the group.\) The Periodic Table Showing the Elements in Order of Increasing Z The atomic radius increases on moving down in the group and decreases on moving left to right in the period. ![]() Thus, least ionization enthalpy on the left and highest negative electron gain enthalpy on the right are the two properties shown by alkali metal and halogen atom of the periodic table. The electron gain enthalpy is the amount of energy released on accepting the electrons by the neutral gaseous atom to form an anion. The halogen atom gains electrons to form anion. The reactivity of the halogen is due to high negative electron gain enthalpy. On the ride side of the periodic table, a halogen group is present. Ionization energy is defined as the measure of the difficulty to remove the electrons from the atom. The atomic radii is the distance between the nuclei of two atoms which are joined with each other. The reactivity of the alkali metal is due to large atomic radii and low ionization energy. The metal tends to release its electrons in the reaction to form metal cation and has +1 oxidation state. The alkali metals are the most reactive metal among the other metal compounds. In the left side of the periodic table alkali metals are present. In the periodic table, the maximum chemical reactivity is at extreme left. Hint:The metals are the elements which release electrons to other atoms in the reaction to form a cation and the non-metal are the elements which gain electrons to form anion.
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