Learn Hardcore Turkish: Okunacak kitaplar masanın üzerinde. - The books to be read are on the table.

Morphology: oku (read) + -n (passive) + -acak (future participle) → okunacak = “to be read / that will be read.”
So okunacak kitaplar = “the books to be read.”

Why is the passive form okunacak used instead of an active form?

Because the noun being modified (kitaplar, “books”) is the thing that gets read (the patient), not the doer. An active participle like okuyacak kitaplar would mean “the books that will read (something),” which is semantically wrong. The passive participle okunacak correctly says “books that will be read.”

How would I say “the books that I will read are on the table”?

Use an active future form where the subject is “I”:

Okuyacağım kitaplar masanın üzerinde. You can add the subject explicitly:
Benim okuyacağım kitaplar masanın üzerinde. A passive alternative that names the agent is possible but less common:
Benim tarafımdan okunacak kitaplar masanın üzerinde.

What’s the nuance difference between okunacak and okunması gereken?

okunacak = “to be read / slated to be read” (planned, intended, or expected in the future).
okunması gereken = “that must/should be read” (necessity/obligation).
Both modify nouns, but the second adds a sense of requirement.

Where is the verb “are”? Why is there no “to be” verb?

Turkish nominal sentences in the present don’t need an explicit “to be.” The copula is zero: Okunacak kitaplar masanın üzerinde literally “Books to-be-read table’s on-top-of.”
You can add the copular -dir for a more formal or categorical tone:

Okunacak kitaplar masanın üzerindedir.

Can I use var in this sentence?

Use var when you’re making an existential statement (“there are …”), typically with the location first and an indefinite subject:

Masanın üzerinde okunacak kitaplar var. = “There are books to be read on the table.”
Your original sentence, Okunacak kitaplar masanın üzerinde, identifies the location of a specific/known set (“The books to be read are on the table.”).
Avoid: Okunacak kitaplar masanın üzerinde var. (sounds off in standard usage).

Why masanın üzerinde instead of masada?

masada = “at/on the table” (broader, can be “at the table”).
masanın üzerinde = “on the surface of the table” (literally “on the table’s top”), more precise for “on top of.”
Both can be correct; üzerinde/üstünde is more literally “on (top of)” and unambiguous.

Can you break down masanın üzerinde morphologically?

masanın = masa (table) + -nın (genitive “of the table”).
üzerinde = üzeri (“its top/surface”) + -n- (buffer) + -de (locative “in/on/at”).
Together this is the genitive–possessive construction: “on the top of the table.”

Is üzerinde the same as üstünde?

They’re near-synonyms for “on (top of).”

üzerinde is a bit more formal/literary.
üstünde is more colloquial.
Both are fine: masanın üzerinde / masanın üstünde.

Do I have to use the plural kitaplar? What if I say kitap?

Use kitaplar for more than one book. If you say Okunacak kitap masanın üzerinde, it means “The book to be read is on the table” (singular).
Indefinite plurals often show up with var:

Masada okunacak kitaplar var. = “There are (some) books to be read on the table.”

Is the subject definite or indefinite here?

In Okunacak kitaplar masanın üzerinde, the fronted plural without var is ordinarily understood as definite/specific (“the books to be read”).
If you want an indefinite reading (“some books to be read”), prefer the existential pattern:

Masada/masanın üzerinde okunacak kitaplar var.

Can I change the word order?

Yes, within limits:

Okunacak kitaplar masanın üzerinde. (neutral: identifies where the known books are)
Masanın üzerinde okunacak kitaplar. (location is foregrounded; sounds like an answer to “Where are the books to be read?”)
Keep the modifier and noun together: okunacak kitaplar must stay as a unit. Forms like “Kitaplar okunacak masanın üzerinde” are not natural for this meaning.

How do I negate this?

Two common options:

Negate the location (they’re not on the table):
Okunacak kitaplar masanın üzerinde değil.
Negate the participle (they won’t be read):
Okunmayacak kitaplar masanın üzerinde. (“The books that won’t be read are on the table.”)

Can I add olan, as in okunacak olan kitaplar?

Yes: Okunacak olan kitaplar masanın üzerinde. It’s grammatical but often redundant. It can add mild emphasis or help rhythm/clarity in longer noun phrases. In short phrases, most speakers simply say okunacak kitaplar.

Why is it okunacak and not okunecek? How does vowel harmony apply?

Turkish suffixes harmonize with the last vowel of the stem:

Stems with back vowels (a, ı, o, u) take -acak → okun- ends in back vowel harmony, so okunacak.
Stems with front vowels (e, i, ö, ü) take -ecek → e.g., gelecek (“coming/future”).