Answer Description
The Intel Core i7 processors are simply too powerful and too resource intensive to be used in most mobile devices, especially phones. ARM 7 and Snapdragon processors use specific mobile friendly architectures, which makes them more common in mobile phones. You may however find Intel Core products in larger tablets and laptops.
Wikipedia
Intel Core are streamlined midrange consumer, workstation and enthusiast computers central processing units (CPU) marketed by Intel Corporation These processors displaced the existing mid- to high-end Pentium processors at the time of their introduction, moving the Pentium to the entry level, and bumping the Celeron series of processors to the low end Identical or more capable versions of Core processors are also sold as Xeon processors for the server and workstation markets As of June 2017, the lineup of Core processors includes the Intel Core i3, Intel Core i5, Intel Core i7, and Intel Core i9, along with the X-series Intel Core CPUs
Intel Core - Wikipedia, the free encyclopedia