Atomic properties Period 2 elements

Periodic function A physical or chemical property of elements that varies periodically with atomic number, 152 Periodic Table An arrangement of the elements in rows and columns according to atomic numbers such that elements with similar chemical properties foil in the same column,... 

There are similar, but smaller, trends in the properties of elements in a column (a family) of the periodic table. Though the elements in a family display similar chemistry, there are important and interesting differences as well. Many of these differences are explainable in terms of atomic size. 

To understand how the electron has been applied to explanations of the periodic table we must start with the discovery of the periodic system itself. The Russian chemist Dimitri Mendeleev announced in 1869 that the properties of elements arranged in order of increasing atomic weight appeared to repeat after certain definite intervals. Yet even as this discovery became increasingly well established, Mendeleev remained strongly opposed to any attempt to reduce or explain the periodicity in terms of atomic structure. He resisted the notion of any form of primary matter, which was actively discussed by his contemporaries, and opposed... 

The periodic system of elements gets its moniker because it graphs how certain properties of chemicals repeat after regular intervals. In the modem table of 117 elements, each is placed across rows in order of increasing atomic number—the number of protons in the nucleus of one atom of each element. There are seven rows, each... 

But the reductionist approach adopted by Bent and Weinhold is nevertheless consistent with their wanting to explain the periodic table through the properties of the neutral atoms of the elements rather than their macroscopic properties. 

Bent claims that the periodic system should be primarily based on the structure of neutral atoms rather than on macroscopic properties of the elements. In doing so he claims support from none other than Mendeleev. Bent also claims to garner support from the writings of Mendeleev in steering clear of the properties of the elements as simple substances in crucial matters of classification of the elements. In fact, the identification of elements as basic substances with the atoms of the elements is... 

The periodic table is a catalog of the elements, each with its own unique set of physical and chemical properties. Each element has a unique value for Z, the positive charge on its nucleus. The number of electrons possessed by a neutral atom of that element is also equal to Z. The different properties of elements arise from these variations in nuclear charges and numbers of electrons. 

A. The phenomenon of periodicity is particularly clear in the melting points of the elements. It is however remarkable, because this is a purely physical property. The melting point is not an atomic property, but is determined by the relationships in the crystal lattice. Therefore the maxima and minima do not coincide with the beginning or end of a period as is the case with the atomic radii and ionization energies. 

Next, we illustrate these properties by discussing them together with some of the atomic properties for the diatomic hydrides of the elements of periods 2 and 3. 

The number of protons in the nucleus determines the chemical properties of the element. That number is called the atomic number of the element. Each element has a different atomic number. An element may be identified by giving its name or its atomic number. Atomic numbers may be specified by use of a subscript before the symbol of the element. For example, carbon may be designated 6C. The subscript is really unnecessary, since all carbon atoms have atomic number 6, but it is sometimes useful to include it. Atomic numbers are listed in the periodic table and in Table 3-1. 

The periodic law is, like all natural laws, a summary of experimental observations. It states that a given property of elements varies periodically when the elements are arranged in order of increasing atomic number. 

Therefore the number of half-filled orbitals indicates the number of bonds that the atoms can form. Elements in the same group of the periodic table exhibit similar chemical properties as they have the same number of valence electrons. We will explain bond formation of one representative element from each main group. The other elements found in the same group generally form bonds in a similar way. 

In this section, you have seen how a theoretical idea, the quantum mechanical model of the atom, explains the experimentally determined structure of the periodic table, and the properties of its elements. Your understanding of the four quantum numbers enabled you to write electron configurations and draw orbital diagrams for atoms of the elements. You also learned how to read the periodic table to deduce the electron configuration of any element. 

Q On which side of the periodic table would you find an element whose atom is likely to form a cation Which atomic property is related to this question ... 

An element s tendency towards partitioning into solid phases is related to its fundamental atomic properties. These properties follow periodic trends, giving rise to the trends shown in Figure 11.5 for the oceanic residence times of the elements. In the broadest sense, these trends reflect the relative tendency of an element towards electrostatic versus covalent interactions. Chemists have devised various measures of this tendency, such as an element s electronegativity and its ionization potential. The latter is a predictor of electrostatic interactions and is defined as the ratio, z /r, where... 

Wolfgang Pauh (1900-1958), an American physicist, was awarded a Nobel Prize in 1945 for developing the exclusion principle. In essence, it states that a particular electron in an atom has only one of fom energy states and that all other electrons are excluded from this electron s energy level or orbital. In other words, no two electrons may occupy the same state of energy (or position in an orbit around the nucleus). This led to the concept that only a certain number of electrons can occupy the same shell or orbit. In addition, the wave properties of electrons are measmed in quantum amounts and are related to the physical and, thus, the chemical properties of atoms. These concepts enable scientists to precisely define important physical properties of the atoms of different elements and to more accmately place elements in the periodic table. 

The configuration of electrons around the nuclei of atoms is related to the structure of the periodic table. Chemical properties of elements are mainly determined by the arrangement of electrons in the outermost valence shells of atoms. (Other factors also influence chemical... 

The most important approach to reducing the computational burden due to core electrons is to use pseudopotentials. Conceptually, a pseudopotential replaces the electron density from a chosen set of core electrons with a smoothed density chosen to match various important physical and mathematical properties of the true ion core. The properties of the core electrons are then fixed in this approximate fashion in all subsequent calculations this is the frozen core approximation. Calculations that do not include a frozen core are called all-electron calculations, and they are used much less widely than frozen core methods. Ideally, a pseudopotential is developed by considering an isolated atom of one element, but the resulting pseudopotential can then be used reliably for calculations that place this atom in any chemical environment without further adjustment of the pseudopotential. This desirable property is referred to as the transferability of the pseudopotential. Current DFT codes typically provide a library of pseudopotentials that includes an entry for each (or at least most) elements in the periodic table. 

The periodic trend of a decrease in atomic radii across a period is readily seen in the Figure 6.4. Other properties related to atomic radii show a similar pattern. Knowing that the elements exhibit a general periodic trend allows us to predict unknown properties for elements and aided in the discovery of unknown elements. The periodic nature of the elements supported the development of the quantum theory. The elements show a periodic pattern in both their properties and electron configurations. The periodic trend in properties of the elements... 

A substance can be classified chemically in many ways. One of the simplest ways to classify a substance is as an element or a compound. An element is a pure substance that cannot be changed into a simpler substance by chemical means. Elements are the building blocks of nature all matter is composed of elements. The periodic table is a concise map that organizes chemical elements into columns (groups) and rows (periods) based on their chemical properties. Currently, there are 118 known chemical elements, with whole numbers 1 to 118. These numbers are referred to as the element s atomic number and give the number of protons in the nucleus of an atom of the element. For example, carbon s atomic number is 6 and each carbon atom has 6 protons in its nucleus. The first 92 elements occur naturally, and those above atomic number 92 are synthesized through nuclear reactions using particle accelerators. Element 118 was just confirmed in the fall of 2006, and by now, more elements may have been produced. 

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