Ładowarka jest na stole.

to be

Breakdown of Ładowarka jest na stole.

• na: on
• stół: the table
• ładowarka: the charger

Questions & Answers about Ładowarka jest na stole.

Why is ładowarka in the nominative case here?

Because ładowarka is the grammatical subject of the verb jest (to be). In Polish, the subject always appears in the nominative case, and feminine nouns ending in -a keep that ending in the nominative singular.

What does jest mean and which tense is it?

Jest is the third-person-singular present tense of być (to be). It corresponds to the English is.

Why is the preposition na used here, and why does stół change to stole?

When na expresses location (i.e. “on” something), it requires the locative (miejscownik) case. The noun stół (table) in locative singular becomes stole.
Example declension of stół:
nominative stół – genitive stołu – dative stołowi – accusative stół – instrumental stołem – locative stole.

Why doesn’t Polish use articles like the or a before ładowarka?

Polish has no articles. Definiteness or indefiniteness is understood from context, so you simply say ładowarka jest na stole without needing the or a.