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

Yes

The spelling, meaning, and grammatical function of "atividades" are identical in both Brazilian and Continental Portuguese. The only difference lies in pronunciation.

In Brazilian Portuguese, the vowels are generally more open, and the unstressed "e" in the suffix "-des" is typically pronounced clearly, often sounding like /i/ (e.g., atividádis). In Continental Portuguese, there is a much stronger tendency toward vowel reduction; the unstressed "e" is much more closed and often becomes almost silent, making the word sound more compressed and clipped.

Brazilian Portuguese examples:

1. Eu tenho muitas atividades para fazer hoje. (I have many activities to do today.)
2. As atividades da escola são muito legais. (The school activities are very cool.)
3. Ele faz atividades físicas todas as manhãs. (He does physical activities every morning.)
4. Quais são as suas atividades favoritas? (What are your favorite activities?)
5. Vamos planejar as atividades da semana. (Let's plan the activities for the week.)

Portuguese (Portugal) examples:

1. Eu tenho muitas atividades para fazer hoje. (I have many activities to do today.)
2. As atividades da escola são muito fixes. (The school activities are very cool.)
3. Ele faz atividades físicas todas as manhãs. (He does physical activities every morning.)
4. Quais são as tuas atividades favoritas? (What are your favorite activities?)
5. Vamos planear as atividades da semana. (Let's plan the activities for the week.)