Final answer:
The incorrectly capitalized word in the sentence is 'Classroom.' Only proper nouns or the first word of a sentence need to be capitalized. The capitalization can convey different levels of formality or mood in writing.
Step-by-step explanation:
The word in the sentence 'He's the tallest student in our Classroom' that is incorrectly capitalized is 'Classroom.'
Common nouns like 'classroom' should not be capitalized unless they are the first word in a sentence or part of a proper noun. In Mateo's messages, we can see how capitalization can indicate formality and mood in writing.
For instance, when referring to 'Prof. Chang,' 'Prof.' is capitalized as it is an abbreviation for 'Professor,' which is a title and hence is correctly capitalized. Similarly, 'Oscar's' and 'Dawson Library' are proper nouns and are capitalized correctly. However, in the casual message about class time, Mateo avoided capitalization, which gives us insight into the informal tone of the message.
The word that is incorrectly capitalized in the sentence is 'Classroom'.
Proper nouns, such as 'He' and 'Classroom', should be capitalized. In this case, 'classroom' should be written with a lowercase 'c' as it refers to a general classroom and not a specific or proper noun.
The correct sentence would be: 'He's the tallest student in our classroom.'