Why do certain words in the Quran written with alif/ madd and others not?

Assalamu alaikum,
Thanks for all the sessions of tajweed, this is really helpful.
My question is about the use of tajweed rules, I wonder if Allah revealed to us, why some words are almost every time pronounced or wrote, with the long Alif (the symbol who looks like a dagger) for example for the words “malaïka” or “sama’ ” contain almost every time or maybe every time a long Alif in Quran.
Is it for the importance of the angels and the sky, or we don’t know, and it is part of the unknown. I hope you understood my question, it is, why certain words contain almost every time a tajweed sign or symbol. Thanks a lot for your answer and the work you are putting in your website/channel/ and more.

The Answer

Wa alikom asslam wa rahmatu Allahi taala wa barakatuh,
Alhamdulilah

You see, every single tajweed sign has a trigger that causes it to exist. The word الملـئكة has madd because it contains an alif and followed by hamza. This causes madd.
But other words like الله contains an alif, but it is not followed by hamza, so no madd is triggered, and so there is no tajweed sign needed.
This is the same with all tajweed rules and signs. When you start learning tajweed, you will understand more what triggers these signs.
If you want to understand why there are certain words that are written in a certain way, then you can check out this lesson in which I elaborate on this issue: https://www.youtube.com/watch?v=6wMwHCa73bM&t

Hope this answers the question.

Hope this answers the question in shaa Allah.Allah knows best.
Asslamo alikom