The noun dickens (lower case d) has no possessive form, it is a word used for emphasizing a question to express surprise or anger (Who the dickens was that?). To some, using the noun dickens is a euphemism for invoking the devil.
The possessive form for the proper noun Dickens is Dickens's. The possessive of all English singular nouns is formed by adding -'s. Singular nouns already ending in -s acquire a new syllable, along with the -'s of the possessive.
The singular possessive form of "Mr. Dicken" is "Mr. Dicken's."
The possessive form is Amos's.
The singular form is goose; the singular possessive form is goose's.The plural form is geese; the plural possessive form is geese's.
Quantum is singular, not singular possessive. The singular possessive form is quantum's.
The singular possessive form is week's.
The singular possessive form is contralto's.
The singular possessive form is aircraft's.
The singular possessive form is frontiersman's.
The singular possessive form is speculum's.
The singular possessive form is herd's.
The singular possessive form is heart's; the plural possessive form is hearts'.
The singular form for the noun families is family. The singular possessive form is family's.
The singular possessive form of wolves is wolf's.