No. Most data and instructions are several bytes long and occupy several consecutive memory addresses.
The memory system merely stores bit patterns. That some of these patterns represent integers, that some represent characters, and that some represent instructions (and so on) is of no concern to the electronics. How these patterns are used depends on the programs that use them. A word processor program, for example, is written to process patterns that represent characters. A spreadsheet program processes patterns that represent numbers.
Of course, most programs process several types of data, and must keep track of how each is used. Often programs keep the various uses of memory in separate sections, but that is a programming convention, not a requirement of electronics.
Any byte in main storage can contain any 8-bit pattern. No byte of main storage can contain anything but an 8-bit pattern. There is nothing in the memory system of a computer that says what a pattern represents.
When first turned on, many computer systems test their RAM by writing various patterns to various locations and then reading the patterns back. Do you think this is a good test?