Algum vs Nenhum

Algum

We use algum, alguns, alguma or algumas according to the gender and number of the word it quantifies.

• Algum dia. (Some day.)
• Traz alguma coisa para comer. (Bring something to eat.)
• Tenho alguns dias de folga. (I have some days off.)
• Há algumas pessoas na fila. (There are some people in the queue.)

The word algum usually translates as some (undefined quantity) in affirmative sentences but in questions, it translates as any (one among several).

• Vou comer alguma coisa. (I’m going to eat something.)
• Há algum problema? (Is there any problem?)

Nenhum

If the sentence is negative, the Portuguese equivalent to any is the word nenhum (not any/none). Similarly, the word nenhum has four forms depending on the gender of the noun. However, the plural forms (nenhuns, nenhumas) are not used very often, since the word comes from the fusion of nem um (not even one). For example, we prefer to say Não apareceu nenhum convidado (Not one guest appeared) instead of Não apareceram nenhuns convidados (No guests appeared.).

• Não quero nenhum bolo. (I don’t want any cake.)
• Não há nenhuma encomenda para ti. (There isn’t any package for you).

Nenhum(a) can also mean also mean neither:

• Nenhum dos dois foi convidado. (Neither of the two were invited.)

In Portuguese, the structure Is there any…? — No, there isn’t any / there is none is the following:— Há alguma mesa livre? (Is there any free table?)— Não, não há nenhuma. (No, there isn’t any.)