Everyone means every person and is synonymous with everybody. 'Every one' is usually followed by 'of' and means each individual or part of a group and can refer to people or objects. 'If you like the biscuits you can eat every one.' Collective nouns which refer to a group can take singular or plural verb forms depending on the meaning of the sentences. So you can say 'The government is' if you are referring to the government as one entity and 'the government are' if you are referring to them as individuals. The difference is often very subtle and both forms can be used in most instances. 'The government is/are hoping to solve the problem soon.'