The plural form for the proper noun is the Hernandezes. The plural possessive form is the Hernandezes'.
Example: The Hernandezes' house is at the end of the street.
Hernandez's
NB Add apostrophe 's'.
e.g.
Hernandez's coat.
The singular possessive is Hernandez's.
Hernandez'
The possessive form is Amos's.
The singular possessive form is herd's.
The singular possessive form is heart's; the plural possessive form is hearts'.
The singular possessive form is lesson's.
The singular possessive form is grotto's.
The possessive form of the proper noun Hernandez is Hernandez'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 speculum's.
The singular possessive form is frontiersman's.
The singular possessive form is aircraft's.
The singular possessive form is week's.
The singular possessive form is contralto'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.