Radium electronic configuration

I he atomic wcighi varies because of natural variations in the isotopic composition of the element, caused by the various isotopes having different origins - I h is the end product of the thorium decay scries, while Ph and " Pb arise Irom uranium as end products of the actinium and radium series respectively. Lead-204 has no existing natural radioactive precursors. Electronic configuration l.v 2s lfc22/j"3v 3//,3i/l"4v- 4/, 4l/" 4/ IJ5v- 5/ "5t/l"bv />-. Ionic radius Pb I.IX A. Pb 1 0.7(1 A. Metallic radius 1.7502 A. Covalent radius (ip i 1.44 A. First ionization potential 7.415 cV second. 14.17 eV. Oxidation... 

This group contains the elements beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). After the alkali metals, they are the second most active metals. Their electron configurations end with ns2. They become positive two charged ions by giving of their two valence electrons in chemical reactions. At room temperature, they occur in a monoatomic structure and they are solid at room temperature. Radium, a solid element, is the only radioactive member of this group. 

Give the electron configurations for sulfur (S), cadmium (Cd), hafnium (Hf), and radium (Ra), using the periodic table inside the front cover of this book. 

An asterisk denotes a radioactive isotope whose lifetime is indicated in the column Natural abundance. When a stable element has several radioactive isotopes, a few ones have been chosen for their interest in different applications. For the radioactive elements, only the isotopes with the longest lifetimes and at least one with a nonzero nuclear spin I are indicated. The electronic configuration of an element with atomic number Z is given in italics in the Name and symbol column. When relevant, the old Group label notation of the periodic table is indicated in brackets in this same column. The radioactive elements francium, radium, and actinium (Z = 87, 88, and 89, respectively) have been omitted. 

This shared electronic configuration has a more pragmatic importance in medicine. The similarity in electron shells allows strontium, barium, and radium to be absorbed in the same way as calcium in human and animal physiology—a phenomenon that leads to both a cause and a treatment for cancer. 

The alkaline earth metals are somewhat less electropositive and less reactive than the alkali metals. Except for the first member of the family, beryllium, which resembles aluminum (a Group 3A metal) in some respects, the alkaline earth metals have similar chemical properties. Because their ions attain the stable electron configuration of the preceding noble gas, the oxidation number of alkaline earth metals in the combined form is almost always +2. Table 20.5 lists some common properties of these metals. Radium is not included in the table because all radium isotopes are radioactive and it is difficult and expensive to study the chemistry of this Group 2A element. 

The seventh period of the periodic table is occupied by a similar series called the actinide series. Beginning with actinium the 5/ electron shell is populated in a matmer analogous to filling the 4/ electron shell in the lanthanide series. A suggested electronic configuration [K2, M6], is shown in Table 9.2. After the alkaline earth radium, additional electrons are added to the 6d and 5/ shells, beginning the actinide series. At the beginning of the actinide series electrons are added... 

Radium is element 88 and is in Period 7 (and Group 2), as shown in Figure 11.25. Thus radium has two electrons in the 7s orbital, and its electron configuration is... 

The last row of elements begins with francium (Z = 87 electron configuration [Rn]7s ) 2nd radium (Z = 88 electron configuration [Rn]7s ), and then continues with the actinide series, hich starts at actinium (Z = 89) and ends with nobelium (Z = 102). The actinide series has rartially filled 5/and/or 6d subshells. The elements lawrencium (Z = 103) through darmstadtium Z = 110) have a filled 5/subshell and are characterized by the filling of the 6d subshell. 

Practice Problem A Without referring to Figure 6.25, write the electron configuration for a radium atom (Z = 88) in the ground state. 

Beryllium and radium are both in Group 2. a Write the electronic configuration of beryllium. [2]... 

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