النظارة الطبية على الطاولة.

Because Arabic often leaves out to be in the present tense.

So النظارة الطبية على الطاولة literally looks like:

• the medical glasses / eyeglasses
• on the table

But it naturally means:

• The eyeglasses are on the table.

This is called a nominal sentence in Arabic. In the present tense, Arabic usually does not use a separate word for is / are.

If you wanted the past tense, then Arabic would use a verb, for example:

• كانت النظارة الطبية على الطاولة = The eyeglasses were on the table.

النظارة is grammatically singular feminine, but in Modern Standard Arabic it can refer to eyeglasses / spectacles as a single item.

So even though English usually says glasses in the plural, Arabic commonly treats it as one object:

• نظارة = glasses / a pair of glasses / spectacles

That is why the adjective is also singular feminine:

• النظارة الطبية

There is also a plural form:

• نظارات

But in everyday usage, the singular often refers to one pair of glasses.

Because it is describing النظارة, which is a feminine singular noun.

Arabic adjectives must agree with the noun they describe in:

• gender
• number
• definiteness

So:

• النظارة = feminine singular definite
• الطبية = feminine singular definite

That agreement is why الطبية ends with ة and matches the noun.

Because in Arabic, when a noun is definite and is followed by an adjective, the adjective must also be definite.

So:

• النظارة الطبية = the medical glasses / the eyeglasses
• نظارة طبية = medical glasses / a medical pair of glasses

This is a very important Arabic pattern:

• definite noun + definite adjective
• indefinite noun + indefinite adjective

You cannot normally mix them here.

على means on or on top of.

So:

• على الطاولة = on the table

This is the natural preposition when something is resting on a surface.

Compare:

• على الطاولة = on the table
• في الطاولة = in the table, which would usually not make sense unless something is inside it

So على is exactly the expected choice here.

This is a nominal sentence consisting of:

1. النظارة الطبية — the topic / subject
2. على الطاولة — the predicate / information about it

So the structure is basically:

• [The eyeglasses] [on the table]

Arabic often uses this structure instead of subject + is + place.

You can think of it as:

• The eyeglasses — on the table.

with is/are understood.

In الطبية, the ل of الـ is not pronounced fully, because ط is a sun letter.

So:

• الطبية is pronounced approximately aṭ-ṭibbiyya

The ط is doubled, and the l sound disappears in pronunciation.

By contrast, in النظارة, the ن is a moon letter, so the l is pronounced:

• النظارة ≈ an-naẓẓāra?
  Actually, more precisely: al-naẓẓāra

So in this sentence:

• النظارة → the l is pronounced
• الطبية → the l is assimilated

Yes. In fully vocalized formal Arabic, the sentence would typically be:

• النَّظَّارَةُ الطِّبِّيَّةُ عَلَى الطَّاوِلَةِ

The case endings are:

• النظارةُ = nominative, because it is the subject/topic
• الطبيةُ = nominative, matching the noun
• الطاولةِ = genitive, because it comes after the preposition على

In normal unvoweled writing, these endings are usually not shown.

Because Arabic prepositions require the following noun to be in the genitive case.

So:

• على الطاولةِ
• في البيتِ
• من المدرسةِ

This is a standard rule:

• preposition + genitive noun

That is why the full form is الطاولةِ with kasra in fully vocalized Arabic.

Yes. الطبية literally means medical, so the phrase can be understood as:

• the medical glasses
• more naturally in English: the eyeglasses
• depending on context: the prescription glasses

In many contexts, النظارة الطبية is the normal Arabic way to distinguish eyeglasses from things like:

• نظارة شمسية = sunglasses

So this phrase often means eyeglasses / prescription glasses, not just any kind of glasses.

You would remove الـ from the noun and adjective if they are both indefinite.

For example:

• نظارة طبية على الطاولة = A pair of eyeglasses is on the table / Medical glasses are on the table, depending on context

In fully vocalized form:

• نظارةٌ طبيةٌ على الطاولةِ

So the key pattern is:

• النظارة الطبية = the eyeglasses
• نظارة طبية = a pair of eyeglasses / eyeglasses

Arabic marks definiteness very clearly in noun-adjective combinations.