- The halogens (/ˈhælədʒən, ˈheɪ-, -loʊ-, -ˌdʒɛn/) are a group in the periodic table consisting of six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and the radioactive elements astatine (At) and tennessine (Ts), though some authors would exclude tennessine as its chemistry is unknown and is theoretically expected to be more like that of gallium. In the modern IUPAC nomenclature, this group is known as group 17.
- Commonplace book (Wikipedia)
Commonplace books (or commonplaces) are a way to compile knowledge, usually by writing information into books. They have been kept from antiquity, and were kept particularly during the Renaissance and in the nineteenth century. Such books are similar to scrapbooks filled with items of many kinds: sententiae (often with the compiler’s responses), notes, proverbs, adages, aphorisms, maxims, quotes, letters, poems, tables of weights and measures, prayers, legal formulas, and recipes. Entries are most often organized under subject headings and differ functionally from journals or diaries, which are chronological and introspective." Commonplaces are used by readers, writers, students, and scholars as an aid for remembering useful concepts or facts; sometimes they were required of young women as evidence of their mastery of social roles and as demonstrations of the correctness of their upbringing. They became significant in Early Modern Europe.