Strontium atomic properties

Stronlianile, 385 Strontium atomic size, 379 chemistry, 382 electron configuration. 378 heal of vaporization, 305 hydroxide, K,p, 383 ionization energies, 379 occurrence, 385 properties, 381 Structural formula, 31 Structural isomers, 327 Styrene, 345 Sublimation, 176 Substance, 28 pure, 29, 65, 70... 

Because mass spectrometers can resolve atomic weights that differ by less than one atomic mass unit (AMU), they are able to measure isotope ratios for a specific element. Many elements have atoms of more than one atomic weight. Although they are chemically identical, isotopes of the same element have a different number of neutrons - which change the weight but not the chemical properties - in the atomic nucleus. For example, all strontium atoms have 37 protons, which define strontium... 

Physical and Chemical Properties Strontium is a member of the alkaline earth elements, with atomic number 38 and atomic mass 87.62. It possesses four stable isotopes Sr (0.56%), Sr (9.86%), Sr (7.00%), and Sr (82.58%) (Emsley 1992). The pure metal strontium, while less reactive than the alkali metals, is a strong reducing agent and requires appropriate handling. Strontium reacts vigorously with water to form SrOH, liberating Hj in the process. In its chemical characteristics it resembles calcium and barium, and has properties intermediate between these two elements. The strontium atom easily loses two electrons in the 5 s level to form the divalent ion Sr " ". This ion occurs in many... 

We reported earlier the first-principles study on the crystal structure and hydraulic activity of P- and y-form belites (Sakurada et al. 2009a, 2009b). In this chapter, we present our DFT simulation results on the study of hydraulic properties of cement phases. Ca-Ca, Ca-0, and Si-0 bond lengths are chosen as a yardstick for making reliable prediction on the hydraulic activity of p- and Y-C2S phases. Moreover, to find a change in crystal structure of P-C2S on substitution of the strontium atom or barium atom for a calcium atom, a periodic boundary condition has been applied on a large supercell (504 atoms, a x 3, b x 3, c x 2) to remove any spurious interactions. 

Properties. Strontium is a hard white metal having physical properties shown in Table 1. It has four stable isotopes, atomic weights 84, 86, 87, and 88 and one radioactive isotope, strontium-90 [10098-97-2] which is a product of nuclear fission. The most abundant isotope is strontium-88. 

As the number of elements increased, so did attempts to organize them into meaningful relationships. Johann Dobereiner (1780-1849) discovered in 1829 that certain elements had atomic masses and properties that fell approximately mid-way between the masses and properties of two other elements. Dobereiner termed a set of three elements a triad. Thus, chlorine, bromine, and iodine form a triad Dobereiner proposed several other triads (lithium-sodium-potassium, calcium-strontium-barium). Dobereiner recognized that there was some sort of relationship between elements, but many elements did not fit in any triad group, and even those triads proposed displayed numerous inconsistencies. 

Calcium is readily absorbed by the body for the building of bones. Since calcium and strontium are in the same atomic group, they have similar physical and chemical properties. The body, therefore, has a hard time distinguishing between the two and strontium is absorbed just as though it were calcium. 

However, other scientists had also attempted to categorise the known elements. In 1817, Johann Dobereiner noticed that the atomic weight (now called atomic mass) of strontium fell midway between the weights of calcium and barium. These were elements which possessed similar chemical properties. They formed a triad of elements. Other triads were also discovered, composed of ... 

We turn now to a very important class of materials that have the formula /IBC3, with the C frequently oxygen. Strontium titanate is a familiar example and one we shall use for illustrative purposes. Titanium is in the D4 column of the Solid State Table, having four electrons beyond its argonlike core. Strontium has two electrons outside its kryptonlike core, so we may think of the six valence electrons as having been transferred to the three oxygen atoms to form a simple ionic system. As we shall see, however, the titanium d states form the lowest conduction band and are important in the bonding properties as well. 

The atomic number of beryllium is one less than that of boron, which follows it on the periodic table. Strontium, which is directly below beryllium in period 5 of the periodic table has 34 more protons and 34 more electrons than beryllium. However, the properties of beryllium resemble the much larger strontium more than those of similar-sized boron. 

That the elements [Hissessed relationships uf a different Hurt was shown soon after the establishment of Dalton s Atomic Theory. As early as 1817, Dnehereiner culled attention to the fact that strontium hud an atomic weight which was very close to the mean of the values for calcium and barium, while these three elements showed dose similarity in both physical mid chemical properties, Tatter he also showed that there are other triads in which the same general relationship exists, such... 

The chemical properties of calcium and strontium provide an interesting example of periodic group similarity. Strontium-90, a radioactive isotope, is a major product of an atomic bomb explosion. If an atomic bomb is exploded in the atmosphere, the strontium-90 formed will eventually settle on land and water, and it will reach our bodies via a relatively short food chain. For example, if cows eat contaminated grass and drink contaminated water, they will pass along strontium-90 in their milk. Because calcium and strontium are chemically similar, Sr ions can replace Ca ions in our bones. Constant exposure of the body to the high-energy radiation emitted by the strontium-90 isotopes can lead to anemia, leukemia, and other chronic illnesses. 

With reference to the periodic table, name (a) a halogen element in the fourth period, (b) an element similar to phosphorus in chemical properties, (c) the most reactive metal in the fifth period, (d) an element that has an atomic number smaller than 20 and is similar to strontium. 

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