Is the word arquivos the same in Brazilian and European Portuguese?

Yes

The word "arquivos" has the same meaning, spelling, and grammatical function in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Continental Portuguese, there is a stronger tendency for "vowel reduction," meaning the unstressed vowels (like the "i" in arquivos) may be pronounced more closed or even almost swallowed, whereas in Brazilian Portuguese, these vowels are typically more open and clearly articulated.

Brazilian Portuguese Examples

1. Não estou achando os arquivos na pasta. (I'm not finding the files in the folder.)
2. Me manda os arquivos por e-mail, por favor. (Send me the files by email, please.)
3. Esses arquivos são muito grandes para baixar. (These files are very large to download.)
4. Eu preciso organizar meus arquivos no computador. (I need to organize my files on the computer.)
5. Você deletou os arquivos sem querer? (Did you delete the files by mistake?)

Continental Portuguese Examples

1. Não encontro os arquivos na pasta. (I can't find the files in the folder.)
2. Envia-me os arquivos por e-mail, por favor. (Send me the files by email, please.)
3. Estes arquivos são demasiado grandes para descarregar. (These files are too large to download.)
4. Tenho de organizar os meus arquivos no computador. (I have to organize my files on the computer.)
5. Apagaste os arquivos sem querer? (Did you delete the files by mistake?)