Francium electron configuration

The alkali metals form a homogeneous group of extremely reactive elements which illustrate well the similarities and trends to be expected from the periodic classification, as discussed in Chapter 2. Their physical and chemical properties are readily interpreted in terms of their simple electronic configuration, ns, and for this reason they have been extensively studied by the full range of experimental and theoretical techniques. Compounds of sodium and potassium have been known from ancient times and both elements are essential for animal life. They are also major items of trade, commerce and chemical industry. Lithium was first recognized as a separate element at the beginning of the nineteenth eentury but did not assume major industrial importance until about 40 y ago. Rubidium and caesium are of considerable academic interest but so far have few industrial applications. Francium, the elusive element 87, has only fleeting existence in nature due to its very short radioactive half-life, and this delayed its discovery until 1939. 

This group contains the elements hydrogen (H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). Although hydrogen is a non-metal, it is placed in this group because of its electron configuration, Is1. 

Predict the atomic number of the next alkali metal after francium, and give its ground-state electron configuration. 

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. 

Predict the atomic number and ground-state electron configuration of the next member of the alkali metals after francium. 

The alkali metals - lithium, sodium, potassium, rubidium, caesium and francium - are members of group 1 of the periodic table, and each has a ground state valence electronic configuration ns. Discussions of these metals usually neglect the heaviest member of the group, francium. Only artificial isotopes of francium are known, the longest Uved, Fr, having n = 21.8 min. 

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. 

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