На полиці стоять книжки, а поруч лежать папка і сканер.

Because на is expressing location here: on the shelf. After на in a location meaning, Ukrainian normally uses the locative case.

So:

• полиця = shelf
• на полиці = on the shelf

A useful contrast:

• на полиці = on the shelf, already there
• на полицю = onto the shelf, movement toward it

So the sentence uses на полиці because it describes where the objects are, not where they are going.

Ukrainian often uses verbs of physical position where English would just say are.

So instead of simply saying books are on the shelf, Ukrainian naturally says the books stand there:

• стоять = stand

This is especially natural for things like books on a shelf, because they are imagined as being upright.

So На полиці стоять книжки is very natural Ukrainian.

For the same reason: Ukrainian likes to describe the physical position of objects.

• лежати / лежать = lie / are lying

A folder and a scanner are typically imagined as lying flat on a surface, so лежать sounds natural.

So the contrast is:

• books on a shelf: стоять
• folder and scanner nearby, probably on a desk or surface: лежать

English often just uses are, but Ukrainian is more specific here.

A good beginner rule is:

• use стояти when something is upright or treated as upright
• use лежати when something is flat, horizontal, or resting on a surface

Examples:

• Книжки стоять на полиці. = Books are standing on the shelf.
• Зошит лежить на столі. = The notebook is lying on the table.
• Пляшка стоїть на столі. = The bottle is standing on the table.
• Телефон лежить на столі. = The phone is lying on the table.

This is not just grammar; it is a very common way Ukrainians describe where things are.

Because together they form a compound subject:

• папка і сканер = a folder and a scanner

Two things together count as plural, so the verb is plural:

• singular: лежить папка = the folder is lying
• singular: лежить сканер = the scanner is lying
• plural: лежать папка і сканер = the folder and the scanner are lying

So the verb agrees with the whole subject, not with just the nearest noun.

Here а is a coordinating conjunction that often means something like:

• and
• while
• whereas
• sometimes a light but

It often links two clauses with a slight contrast or shift of attention.

In this sentence:

• На полиці стоять книжки, а поруч лежать папка і сканер.

the idea is something like:

• There are books on the shelf, and nearby there is a folder and a scanner
• or Books are on the shelf, while nearby a folder and scanner are lying

So it is not a strong contradiction. It is more of a gentle contrast between two parts of the scene.

Поруч means nearby, next to it, or beside.

In this sentence it works as an adverb, so it can stand on its own:

• поруч лежать папка і сканер = nearby / next to it lie a folder and a scanner

The context tells us what they are near, probably the shelf or the place being described.

If you want to say next to a specific noun, Ukrainian often uses:

• поруч з
• поруч із

For example:

• поруч із столом = next to the table

So:

• поруч = nearby
• поруч із чимось = next to something

Both are possible, but they emphasize slightly different things.

На полиці стоять книжки is a very natural way to introduce what is in a place. It starts with the location, then tells you what is there.

This pattern is extremely common in Ukrainian:

• place first
• then verb
• then the thing located there

So it feels like:

• On the shelf, there are books

If you say Книжки стоять на полиці, the focus shifts more toward the books themselves.

So the sentence uses a very natural descriptive word order.

Yes, you could. It would be grammatical.

• На полиці є книжки = There are books on the shelf

But it sounds less vivid and less physical than стоять.

Compare:

• є = simply states existence
• стоять / лежать = describes actual position

So:

• На полиці є книжки = there are books on the shelf
• На полиці стоять книжки = the books are standing on the shelf

Ukrainian often prefers the second kind when the physical arrangement matters.

Yes, both are real Ukrainian words for books, but they come from different singular forms:

• книжка → книжки
• книга → книги

Both книжка and книга mean book. Very roughly:

• книжка often sounds a bit more everyday
• книга can sound a bit more neutral or formal

In many situations they overlap a lot.

So in this sentence, книжки is just a natural lexical choice.

Yes. They are the subjects of the verbs, so they are in the nominative.

Forms here:

• книжки = nominative plural
• папка = nominative singular
• сканер = nominative singular

Even though папка and сканер are singular individually, together they make a plural subject, which is why the verb is plural: лежать.

Because а is joining two separate clauses, each with its own verb:

• На полиці стоять книжки
• а поруч лежать папка і сканер

In Ukrainian, when coordinating conjunctions like а connect full clauses, a comma is normally used.

So the comma is standard punctuation here.

Because Ukrainian does not have articles like English a/an and the.

That means a noun like книжки can mean:

• books
• the books

and папка can mean:

• a folder
• the folder

The exact meaning depends on context.

So the sentence does not need separate words for a or the.

These are 3rd person plural present forms:

• стоять = they stand / are standing
• лежать = they lie / are lying

That matches the subjects:

• книжки = plural
• папка і сканер = together plural

A quick comparison:

• книжка стоїть = the book is standing
• книжки стоять = the books are standing
• папка лежить = the folder is lying
• папка і сканер лежать = the folder and scanner are lying

So the -ть ending here is part of the normal plural present-tense form.

It can do either, depending on context.

In Ukrainian, the present tense often covers both:

• what is there right now
• what is generally arranged that way

So this sentence could mean:

• right now, the books are on the shelf and the folder and scanner are nearby
• or more generally, that is how the room or workspace is set up

Nothing in the grammar forces only one interpretation. Context decides.