The norm in mosques is: Women & Men pray separately. In Islam, men praying in congregation get more reward then praying at home (and are sometimes required to pray at the mosque). For women, it's the other way around (more reward when prayed at home and it's not obligatory). Most mosques have a prayer hall for men & women. Usually less women come anyway because of the reason just explained, which usually means mosques have larger prayer hall for men than women. Some, due to lack of area they can build on, don't have space to build a prayer hall for women and thus just use the maximum capacity for the men because these are obliged to go pray at the mosque at least once a week on Friday. For women it's not obligatory to pray at the mosque.