Noon Saakin & Tanween Rules
Idgham bila Ghunnah إِدْغَام بِلَا غُنَّة
Merge without nasal hum — when followed by ل or ر.
When a noon saakin or tanween is followed by lam or ra, the noon is dropped into the next letter with no ghunnah. The merger is complete and the next letter takes shadda.
Quran examples
مِن لَّدُنْكَ
Noon + lam → idgham bila ghunnah. · 3:8
غَفُورٌ رَّحِيمٌ
Tanween + ra → idgham bila ghunnah. · 2:173