15
What is made from only one type of matter and cannot be separated by physical methods? *

Pure substance

Explanation:

A pure substance has a constant composition and cannot be separated into simpler substances by physical means.

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

→