ARM7 Memory model (Flash, SRAM, registers. ...)
ARM, even ARM7, is a very broad design. Documentation for the common parts can be found in ARMinc's documents, or in general books like Furber. 

Details about a specefic chip (like its memory map) are to be found in the manufacturers documents, often split between a datasheet and a user manual.

When an ARM7 start from a reset, it loads the first interrupt vector (the word at address 0) into the PC. That's all, after that it is up to the code.

ARM7 is a CPU design (with some things around the CPU). This design is put in a chip by a manufacturer, along with anything he wants to include. Hence it depends on the specific chip whether all memory and peripherals are on the chip, external to the chip, or a combination.