Just to add some more information to Clay's answer.
"Alguno" is declined in Spanish as an adjective. Its original form is "alguno". Now, this word does not entirely correspond to "some". "Some" is used in English to refer to plurals or partitive.
I will take some of those books (referring to plural)
I will take some of that food (this is partitive, meaning it does not take the entirety of "one" but a part of "one").
If you say the first, in Spanish will be:
Tomaré algunos de esos libros (plural form of "alguno").
If the second, you can say:
Tomaré un poco de esa comida. (a bit).
Tomaré algo de esa comida. (some).
As Clay said, "alguno" declines acording to gender and number. The possible declensions are:
Alguno (mascunline singular)
Algunos (masculine plural)
Aguna (feminine singular)
Algunas (femenine plural).
Take into account that singular masculine adjectives in the attributive position (before the noun) in Spanish drop the "o".
El auto es bueno = The car is good.
El buen auto = The good car.
Alguno de esos días = one of those days.
Algún día = some day.
I hope this helps.