Learn Italian: Ci sono alcuni limoni nel sacchetto. - There are some lemons in the bag.

Both words mean "some", but they work differently. Alcuni is used with plural nouns, which is why it matches the plural limoni. Qualche is always followed by a singular noun. You could change this sentence to use qualche limone and it would mean the exact same thing!

Why is it ci sono instead of c'è?

Ci sono means "there are" and is used for plural objects, like our lemons. If there were only one lemon in the bag, you would use the singular c'è ("there is"), as in C'è un limone nel sacchetto.

Is limoni masculine or feminine?

It is masculine. The singular form is il limone. Nouns ending in -e in the singular can be masculine or feminine, so they are tricky! Here, the masculine plural adjective alcuni is a great clue that limoni is masculine.

Why does the sentence use nel instead of just in il?

In Italian, when the preposition in (in/inside) meets the definite article il (the), they must combine into a single word. In + il creates the combined word nel. You will never see in il written as two separate words.