قَامَ زَيْدٌ — Zayd stood.
قَامَ: past verb.
زَيْدٌ: nominative subject.
بَعْلَبَكُّ مَدِينَةٌ — Baalbek is a city.
بَعْلَبَكُّ: topic; a compound proper name with a fixed first part and nominative second part.
مَدِينَةٌ: nominative predicate.
قَامَ زَيْدٌ is a clause; بَعْلَبَكّ is one compound noun, not itself a sentence.