Comparing the First and Second Classes

Noun Case Classes: Type 2 — Sound Feminine Plural

First class: زَيْدٌ
Nominative: زَيْدٌ — ḍamma.
Accusative: زَيْدًا — fatḥa.
Genitive: زَيْدٍ — kasra.

Second class: مُسْلِمَاتٌ
Nominative: مُسْلِمَاتٌ — ḍamma.
Accusative: مُسْلِمَاتٍ — kasra.
Genitive: مُسْلِمَاتٍ — kasra.

Both classes use ḍamma for nominative and kasra for genitive here. The key difference is the accusative sign.