Block (periodic table) the s-block, with its outer (and only) electrons in the 1s atomic orbital, although its chemical properties are more similar to the p-block noble gases due to its full shell. In addition to the blocks listed in this table, there is a hypothetical g-block which is not pictured here. The g-block elements can be seen in the expanded extended periodic table. Lanthanum and actinium are placed under scandium and yttrium to reflect their status as d-block elements, as they have no electrons in the 4f and 5f orbitals, respectively, while lutetium and lawrencium do. The s-block is on the left
Alphabetical order Unicode Collation Algorithm, which can be used to put strings containing any Unicode symbols into (an extension of) alphabetical order. It can be made to conform to most of the language-specific conventions described above by tailoring its default collation table. Several such tailorings are collected in Common Locale Data Repository. For more details, see . The principle behind alphabetical ordering can still be applied in languages that do not strictly speaking use an alphabet – for example, they may be written using a syllabary or abugida – provided the symbols used have an established ordering. For logographic writing systems, such